@KurtinStGeorge & SerScot
At the end of PG when Harry is talking to Eb, I think it is revealed that the only reason the Council didn’t kill Harry was because Eb personally vouched for him, similar to how Harry did for Molly. This is why Harry, like Molly was placed under the Doom, although I’m unsure if Eb was also placed under it, like Harry is for vouching for Molly.

You have my statement backwards.  It was lightly defended after the attack not before.I'm okay with some of the bones being the attackers.  But someone threw hellfire against the walls.  And the bulk of the dead are in the passage, inside the fortress are the trolls and goblins.  So there was one hell of a fight.  The bulk died in the tunnel or died trying either to keep them out or trying to get past the defenders, but once they got in, they were in.  And they killed the Palace Guard.  And then what?  Surely the the residents of Winter would have their vengeance on at that point.  They're quick enough when Harry throws Summer fire.  The attackers never breech the center tower where the wellspring is.  So they kicked the door in and left?
Not quite.    Mab knows who the attackers are, but not who sent them.  She defends against the enemy she knows and protects her center.

There were thousands of Palace guard who perished in the assault, which is one of the reasons I don’t believe Mab suckered the attackers into the assault. I’m not sure where you’re getting the link between attacking the walls of AT & it summoning all of Winter’s forces - the only thing we saw capable of that was Harry throwing Summerfire within the spire where the Wellspring lies - we know the attackers didn’t get this far.

Why the assault was unable to breach the spire in the courtyard is a good question. Perhaps Mab/ her forces were able to kill the wielder of Namshiel but unable to collect his coin (presumably whisked away by his cohort) which stopped the assault. Or perhaps the attackers realized that the spire was impregnable with the tools they’d brought (since they didn’t have a necro-god with them) - they’d need a god’s Power to breach it.

The fortress in undefended, accept by the fetches, Yet everything that was important is still there.  The prisoners, Mab and the wellspring.  Given the events of Summer Knight, the prisoners are important if for no other reason then the loss of the power  of Slate's mantle would shatter Winter, which we can infer from the reaction of Titania when the Summer Knights mantle was hidden.  And Lea is described as the second most powerful person in Faerie, and she's even more dangerous turned.  If she didn't slow the passage of time at the fortress why isn't the castle fixed and some kind of guard in place.  And why is that portal at the theater available yet.

Jim's playing with time in this whole sequence.  The dead are bones, Thomas calls this out and Harry shrugs.  Jim's obfuscating.  I would give a lot to know why.  I can hear him cackling.Note that Lily holds the portal open, which is the key.  One portal is a locked room to locked room, the other is a theater into the wilds of Faerie.  No maps and no GPS   The screen is the link.

By your theory of the attack happening nearly a year ago, yes Mab keeps her fortress undefended for a while, but if the attack happened a few days/ weeks before PG, then it would make sense as to why the only people/ beings in AT are the ones Mab allows in there - one of the reasons I believe Mab was controlling Eldest Fetch.
At the time of PG (which occurs in the summer), Mab/ Winter are weak, which is a much better time to attack them than DB, which is on Halloween during when Winter is stronger. Mab would also be more afraid of Summer attacking during the summer than she would of them attacking in Winter.

The assault was stopped by Mab before they could get to her ‘vault’ within the spire - the way it reads to me, this was a hard fought victory for Mab, not an ingenious plan to sacrifice thousands of her Palace Guard for an ephemeral victory.

They sent a small army to achieve  a specific purpose. A few details.  All the dead that we know about died when hellfire was thrown at Arctis Tor and belonged to the defenders.  No bones of any of the attackers is seen, and the only living beings at Arctis Tor that are revealed are the fetches. The portcullis is blown apart, yet the tower is intact.  There is no indication that anything other than the fight in the courtyard occurred.  And if Mab is so frightened of an attack occurring at Arctis Tor again why is it so lightly defended.  One Wizard, one White vampire and two mortal females knock on the door and make their way to the Well Spring with the aid of an automatic door.

Hmm the text does not support this - unfortunately I have the audiobooks so I can’t copy paste the exact text, but if you re-read the scene where Harry & Co. first make it out to Arctis Tor (Chapter 36), there are subtle hints that other things were at play here. For example, when Harry is examining the bones at the entrance to the city (50 yards from walls), he notices that some bones were “pulverized to dust in some places” & “warped like melted wax in others”, combined with the fact that he notices acid had pitted the walls of Arctis Tor & smells hellfire in some of the other larger craters on the same wall tells me that there were forces in addition to Hell playing a part in the assault.

By the time Harry gets to the main gate, he is wading “shin deep through bones. Whoever they had been, thousands of their kind had perished here... Where the gate arched beneath the fortress walls, there were still more bones, waist deep on me”. In chapter 37, as Harry goes deeper into Arctis Tor beyond the gateway he notes that there are so many bones that he can longer walk through them, he has to walk atop them.
Harry explicitly notes that the courtyard is littered with the bones of Mab’s defenders. “Echoes bounced back & forth in the courtyard, somehow carrying a tone of disapproval & menace with them. Bones spilled out in a wave from the gate, rapidly tapering off after a few yards. Beyond that, were only scattered groupings of bones.” Harry notes these are trolls, 13 of Mab’s personal guard. He then notes that the “remains of perhaps a thousand creatures lay scattered about”, mentioning that even in GP when he let loose, he was only able to fry a bunch of Ramps/people, nothing on this scale. He goes on to note while examining the remains in the courtyard that “the littler ones were goblins, foot soldiers.... these trolls were her [Mab’s] personal guard, covering her retreat to the tower maybe. Some of them got taken down along the way, others made a stand at the tower’s base, died there.”

This shows that the either the fortress was not lightly defended or the army attacking was not small, since Harry is unable to identify the bones this far in (except the courtyard). There was clearly a substantial battle, & while most of Winter’s troops were at the Summer border, there were clearly thousands of Winter defenders who gave their lives during the assault on Arctis Tor.
The presence of thousands of bones in the courtyard - those of goblins & trolls decimated by hellfire shows that the attack made it fairly deep into the fortress - but the attackers were unable to breach the spire for some reason (where Molly is held).
The entire reading of Harry’s thoughts as he makes it to the spire does not read to me like Mab masterfully sacrificed thousands of her subjects just to see who would come to attack her fortress.

I'm not suggesting any time traveling portals, I am simply saying that Mab does something similar to what we know that Maeve did.  If Maeve can slow the rate of time for the forces returning to the border to give Summer the time to carry out attacks against the Reds then one could presume that Mab could stretch time to slow any forces attacking her stronghold.  And one year after the incursion the Reds are still moving in Faerie unless we assume that Summer sends her troops to the mortal realm to strike at the Reds.

This is an interesting idea & one I hadn’t thought of. So you’re saying that Mab figures out that someone from Summer is involved in the assault on Arctis Tor, so she sends all her troops to the Summer border & then slows down time at Arctis Tor for nearly a year (while only a few days pass at AT) so she can deal with the assault?

Definitely a cool theory, although I’m not so sure that Lily was involved in the initial BC assault - there seems little need for it. And Mab doing this would definitely complicate the complex timeline of events considerably.

Whatever happened at Arctis Tor happened at the heart of Winter.  It takes all the Summer Lady's strength to hold the portal open.  If the portal is the path the assault on Arctis Tor occurs through, then it seems reasonable to assume that someone of at least her power level was required to do the same for the forces involved in the assault.  If Mab knows what happened she may not know who aided the BC to make it happen.  And the list of suspects who could aid them is short.  And Summer is the only true credible threat.  Summer is the only force that could attack from the border of Winter and hope to win through.

Now tally the forces.  Lea is down, the Winter knight's power is not in play.  And Mab has to at least be suspicious that Lea has compromised others in the time she has had to spread the contagion.(which we know to be the case)  And may fear that Aurora did something similar to Summer.  She has to play defense,  hunker down and ride it out until the Courts are back at parity and she has the freedom and forces to move against her enemies.  And picture this against the background of what we know Maeve wasn't doing, which was keeping the army fed with troops.

It still seems easier for Maeve to have been the inside help the BC needed to open a direct portal, although even this is not necessarily true given how Harry is able to open a portal to Hades in SG, without Hades’ help in doing so.

I cheat.   In my theory the portal was set up a year ago, not during PG.  And besides, Jim cheats.

I had considered that but abandoned it because I couldn’t come up with why? So let’s assume the BC attacks Mab through a time traveling portal (since she can control portal access according to you, why didn’t she stop this?) that brings them out a year ago during DB. Why? As of PG, the BC is aware their other ploys in DB (Darkhallow & eliminating wardens+SC) has failed - if they are using time travel, wouldn’t it make more sense to go back & try to succeed at the Darkhallow? Their necro-god would then be able to take on Mab & breach Arctis Tor without too much issue.
What about Odin’s law of conservation of history? He explicitly says that it is much easier to shape the future than alter the past.

The Faerie war took place in Chicago over Chicago, the point was to give Winter the Summer Knights Mantle.  It wasn't an invasion of Winter.  It isn't that it couldn't work the way you think, but I'm limiting myself to things I know did occur to supply motivation for those things that I think occurred.  So I know that the BC hit Arctis Tor.  So the motivation for Winter going to the Summer border is based on that.  Mab knows who the people were who participated in the raid.  She says as much.  But knowing who was behind it is another matter. 

Hmm, Nemesis was trying to start a Faerie war by using the SK mantle as the trigger. Aurora was also aware that her actions would lead to war but saw it as collateral damage to end the ages old conflict.
I also do not understand the link you’re making with the BC assault on Arctis Tor & therefore Mab sent her troops to the Summer border. Are you implying that someone from Summer was involved in the assault & that is why Mab sent her troops there for a year?

I read it like this. The assault team enters through the portal and makes their way to the fortress.(they had to get in close somehow)  Mab rallies her guard when they are spotted.  She makes for the wellspring to defend it if worse comes to worse.  Then Thorned Namshiel throws Hellfire to break the portcullis.  Every body in Winter senses this and  takes off hell bent for leather to the fortress.  He uses hellfire again in the courtyard to kill the guard at the tower.  Like Harry he senses the Winter forces coming.  Maybe Mab is bending time against the attackers.  And to paraphrase a song, anything Maeve can do, Mab can do better.  Throrned Namshiel is outta time. Getting trapped inside the fortress walls is something he would like to avoid.  He scoots.

This would make the BC seem like rank amateurs - they sent 1 powerful sorcerer with a small army to take on Mab at Arctis Tor??! Considering the BC in DB sends overwhelming power to further strategic goals (like summoning Outsiders & their atrocities against the WC), that seems like an under-powered move with a low chance of survival. Nobody believes that Namshiel could take on Mab, especially in her demesne.
For the attack to have been in line with the other BC ones in DB (a parallel you’re drawing in your theory), it would have to be a lot more savage & threatening, with Mab just about pulling out a victory.

@morriswalters
I think one of the issues is that we don’t know if Mab ordered her troops to the Summer border before or after the assault on Arctis Tor.
You seem to think that she does it after the assault - why? By doing this, she effectively locks up Summer’s troops for nearly a year as well, giving the Ramps free passage during that time, while she stays undefended at Arctis Tor.
There is a fair amount of evidence that the events of PG were set up a year ago (like the Summer/Winter army stalemate, Molly getting in trouble etc), showing that this is Plan B for the Black Council since one of their own didn’t become a necro-god.
An issue with your theory regarding the BC assault being launched through the portal at the Con would be that it places that assault on Arctis Tor on my timeline of it happening & not a year ago like you are positing.

My theory is that Mab placed her troops at the border before the assault - the only reason for this would be that she had a strong suspicion that the biggest threat to her purpose would come from that direction. This would make sense if Maeve lies to Mab, telling her that Lily is likely Nfected - Maeve would be able to convince Mab of the ‘danger’ posed by Lily because Maeve is manipulating a lot of Lily’s actions. Remember, Aurora was almost able to start a Faerie war by having her own Knight killed - she didn’t need to move any troops around. Titania is clearly in mourning for Aurora & not all that interested in the fate of the world as seen in CD. So Mab, convinced by Maeve that the Nfected Lily is setting plans in motion to threaten Winter, places her troops at the Summer border, leaving Arctis Tor fairly light on defense. This gives the BC the opening they need to attack, when they think Mab has been lulled into a false sense of security.
This also answers the question regarding everyone’s interest in Molly - believing that Lily has been Nfected, Mab decides to replace her with Molly (hence the seemingly throwaway line in CD where she tells Harry that she’d originally considered Molly to “be a better candidate for Summer”). Maeve of course leaks this to the Black Council, who decide to Nfect Molly for real. This is why Mab whisks Molly back to Arctis Tor as soon as she is able.

Regarding the portal - I mean there is one explanation - Maeve can also create portals to Arctis Tor. There is no evidence that Mab can control portal-access to her realm, or that Hades can - I think this is one of the benefits of free will. If they could, why would they need defenses or guardians?
Also why would Mab need a portal to get Molly back to Arctis Tor? Surely she can just appear wherever she wants, unless you’re suggesting that every time Mab comes to Chicago she enters through Pell’s theater? We also know from SK that there are portals to Winter in Undertown.
The attacks on the Con have been planned a year in advance - this is why Darby Crane was invited back then - he was always going to be the fall guy for this.
An alternative reason for the attacks could be to keep Harry & Michael busy trying to solve them while the BC is able to go about its business. This theory is admittedly light, because I do believe that more was going on with the attacks, especially with your points about the portals.

@morriswalters
Regarding Winter & Summer not attacking the Ramps - I gave you an alternative & plausible theory as to why - Maeve lies to Mab about Lily being Nfected.
The theory you are proposing would require Mab to remain in a destroyed Arctis Tor alone for a year (or a long time anyway given the flow of time in Faerie) with no front gates anymore, & it would only be her defending the entire city - given that the Black Council is not vanquished, this would be extraordinarily ballsy of her given everything that has happened. She wasn’t able to kill the wielder of hellfire for a while later (even then Michael did it) so he’s certainly out there during the events of PG, not to mention the other BC agents scattered throughout the world. On top of that, she sends away her army to stymie Summer as well which ends up helping the Ramps & BC in the short-term - what would be the purpose of this?
Convincing the world that she was crazy would not suffice - what is the benefit? Clearly her true enemies wouldn’t underestimate her since by your theory, she handily won the attempted assault on Arctis Tor.
Also why would Mab be pressured to send help during DB? It seems pretty clearly to be the responsibility of the White Council, who end up sending a team & deputizing Harry to stop it. I don’t understand the link you are drawing between the Arctis Tor assault & the timing of DB... the only thing we can infer is that the attack happened after she appeared in place of Lea in DB.

Regarding Maeve being behind the latter 3 attacks including Fool Moon garage - why would the Scarecrow kill Glau first then? If anything it should’ve struck at Thomas or Harry since Madrigal & Glau were doing things beneficial to Nfected Maeve? Glau is even suspected of being a BC agent.
On the whole, I like your point about both Mab & Maeve being responsible for different attacks though, it makes sense.

I disagree about the assault not getting very far - Harry explicitly states while examining the damage on his way to the ‘penthouse’ that an entire section of remains are from Mab’s personal guard who died defending her way to the Wellspring. That and the fact that Mab, Molly & Eldest Fetch are the only beings alive in Arctis Tor when Harry & co. take their field trip there makes me think that Mab won a costly victory that required her to retreat to the stronghold within her castle.

So are you saying that Mab was responsible for the first attack on the Con & Maeve for the other 2?

@peregrine & isoycrazy
I mean Ramírez knew that before the soulgaze (hence be pulled a knife on her pre-Soulgaze), after the soulgaze he seems to be telling her that his guard is not up to dissuade her.