Acryn is in chaos - Coles on the streets, Corlo running the city, and the end of the world now very much nigh. For the city's frankly enormous population of ne'er-do-wells, this is a prime opportunity to get very, very rich.
Those of you who move in dodgy circles will be aware that one Viola Morel is recruiting thieves, mages and metaphysically unsound personages for a heist that promises great risk and great reward. The target, if typical Acryn chinese whispers are to be believed: the vaults of the College of the Stars.
The party are hired by a mage calling herself Viola, to sneak into the college of the stars and retrieve the Dragonskin Grimoire, which is apparently being used as a power source for some unethical experiments. Viola gives Lionel a small cube which she claims will help them to open certain locks in the vaults. She then covertly possesses Jeremy, identifying him as the most weak-willed member of the party, and sits inside his head to keep an eye on the group.
The first lock on the vaults requires an understanding of the beliefs and opinions of the student body as a whole, so the party enter the college to chat to some students. They immediately stumble across wizard fight club, where Lionel accepts a grossly unfair duel against three mages who insist that they are a single entity, and of course gets hammered. Emilio makes ten riel betting on this. Jeremy takes the opportunity to enthrall Lionel under the guise of healing him. The club is interrupted, however, by a horrible picasso-esque monstrosity that pops in and out of existence, whispering horrible things at the party and causing temporary insanity. Upon defeat, it fades out of existence – the mages say that this is not the first time such an entity has appeared, and that these attacks have increased in frequency over the past few weeks.
The party gain the requisite knowledge to open the first gate (the students believe that scribing is the best rite, they have no clue about current politics, and they would happily jump into a dragon for extra funding) and progress through more traps, including glyphs on the vault walls that cause Marcus to act like a chicken and Lionel to confess his friendship with a Traitor Priest. Arriving at a series of obstinate animated doors, the party have to subdue some very tame Tyrant Lizards – Jeremy takes the opportunity to thrall Hardy, who is managing to flip between Harbinger and Scion in pretty much the most sub-optimal order possible. They are also jumped by another of the creatures encountered above ground, which whispers things like 'I AM AWAKE' and 'SOON I SHALL BE FREE'. Predictably, the party do not heed these warnings.
The party finally enter the section of the vaults belonging to a wizard known as Ashel, who was effectively stuck down here by her fellow mages to prevent her experiments from killing people. The party encounter what appear to be living mana crystals symbiotically linked to animated corpses, who introduce themselves as Ashel's children. They are all evidently magically powerful – one of them notices that somebody is inside Jeremy's head and tells him so, but sadly Jeremy already has so much weird stuff in his head that he assumes this is normal. Another Child extracts painful memories from several of the party, turning them into small glass marbles which the group hang on to. The leader of the Children, Lasarti, convinces Lionel to touch a dormant mana crystal, which turns into a crystalline skeleton resembling a more childlike version of Lionel. This creature calls itself Coll, and tries to convince the party to let it temporarily inhabit their body. Lionel does so, but not before half the party mishears 'Coll' as 'Cole' and tries to jump the poor thing. Marcus tries to attack the Children, the party tries to hold back Marcus, and Lasarti angrily orders them all to leave.
The party uses the cube to pass a gravity-warping trap corridor and then arrives at a makeshift prison facility filled with absurd entities encountered and locked up by the college. While Viola's cube gets to work opening the door, the party have lunch with the prisoners. Things happen:
Eventually the cube finishes its work and the party enter Ashel's chamber. As soon as they do, Viola emerges from Jeremy and rushes towards the cloaked figure of Ashel, ranting and raving that they'll be reunited and they'll do things differently this time. Ashel is a corpse, and has been for some time. Viola is heartbroken. The party is confused, and only become more so when the cube violently explodes. Hardy detects that they are now in neither flux, nor consensus, and is very put out by this. Viola collapses – surgery detects that something has been effectively puppeteering her for about a year. At this point, impossible geometries unfold from the walls and attack, just as a pair of animated swords – The Unifier and The Dissolver – knock politely on the door and attempt to Unify and Dissolve the party respectively. The Unifier promptly unifies Marcus and Hardy, causing the Orb from earlier to manifest and fly away down the corridor, booping.
The party survives the sensory assault of the impossible geometries, defeat the Dissolver (which Jeremy decides to use as an actual weapon, much to its consternation), and access Ashel's notes, detailing that she and Viola used to work together until they had a spat over the creation of the children, and Viola blew up part of the college, swearing revenge. Jeremy enthralls Viola's temporarily braindead body and commands it to follow them, just as more geometries appear. The party climb up Ashel's chimney into the main courtyard, where they discover that the cube appears to have sent the entire college into Carlaeon.
The mages, particularly headmaster Fractura, are very put out by this, blaming the party and insisting that they fix it. They manage to partly restore Viola, and figure out that Carlaeon exploited her obsession to sneak the cube, a very powerful artifact, through the college's defences, where it could freely open a Hole in the World. They identify several ritual gubbins that will be needed to reverse the effect and bring them home, but to do that the party will have to venture out into Carlaeon to find them. Accepting that they are largely at fault, the party do so, taking the Dissolver and convincing the Unifier that it should be friends with them. Hardy wields the Unifier. Lasarti shows up to guilt-trip the party.
Heading out, the party notices a huge, hanging sphere of architecture inside Carlaeon, the same thing that Jeremy keeps seeing. Fighting through waves of Carlaeon gribblies, the party find the college building to find it being deconstructed by creatures that look like horribly elongated copies of Eyeless Joe, who are taking everything within it to the Sphere. Following these servitors, the party arrive at the Sphere to find it occupied by thousands of Dragonborn, and, at their head, Ishvala, The Engineer.
Ishvala has been stuck here for hundreds, if not thousands of years. It was able to expand its soul into the Sphere and merge it with Carlaeon, forming a part of the dragon that belongs to it – Carlaeon's monsters pointedly do not attack the Sphere or the servitors. Inside, Ishvala has complete omnipotence, but neither it, nor its creations, can leave the sphere – if it does, the civilization it has built will collapse as the sphere ceases to be. Ishvala has engineered Ashel and Viola's experiments to bring people to it that could take its place.
The party discuss the ethics of this, but Emilio offers to take over the Sphere, the prospect of omnipotence being well worth the cost in his eyes. The Dissolver tries to convince Jeremy to dissolve this world instead, but Jeremy refuses. Emilio makes the transfer, and is last seen contentedly lounging on a pile of gold and riches. He also discovers that Ishvala is the only real dragonborn here, the rest being just constructs, but is not overly bothered by this. The party retrieve the necessary ritual components and prepare to leave.
Leaving Emilio behind, the party use a shortcut suggested by Ishvala, unifying certain gateways within Carlaeon to get right back to the college. This leads to a fraught fight, in which Carlaeon's mouths taunt them while Hardy uses the Unifier to position the gates. On occasion, a member of the party who is in severe trouble receives unexpected healing, apparently with no source. Jeremy finds this confusing and troubling. As the party near the last gate, Marcus betrays the group, SHATTERing some of the ritual components. This leads to a brutal battle at the last gateway in which Marcus is finally killed by Hardy, having gotten back up twice. Jeremy is bitten by a horrible gnashing pyramid thing, which leaves his face looking much like the picasso monsters from earlier.
Returning to the college at last, the mages try to jury-rig a slightly different version of the ritual, but this takes longer, and the party must defend that ritual from Carlaeon's hordes. However, the mages suddenly realise that the ritual is going too well – something is actively helping them, and in this place only one being can do so – Carlaeon. Hardy realizes that the monsters attacking them aren't really trying to hurt them, and the mages discover to their horror that Carlaeon has possessed the entire college – if they try to take it back, they will bring a major fragment of Carlaeon into Acryn. Hence the earlier healing and the shouting maw – the dragon has been trying to scare them into using the ritual without paying close enough attention to figure out what's really going on.
The party thus face a choice – save everyone in the college at the cost of a draconic incursion, or open a portal to evacuate just a few. Coll points out that the Children are too far away to escape in the latter plan – Lionel wants to go back, but Jeremy insists that they just go. Carlaeon's attackers now fight properly, and bits of the college begin to fight the party. Hardy fully embraces their anomalous nature in order to save as many people as possible, and together the group hold off Carlaeon while Fractura opens a rift, using their newfound trust in one another to resist the derangement caused by the possessed college. The rift stays open for about three minutes, long enough to save about fifty mages, before the party go through. Fractura closes the portal from the draconic side, staying behind with the majority of the college as Carlaeon roars in frustration. Lasarti and the children rush to the portal, but it closes on Lasarti's outstretched arm, leaving Coll as the last of his species.
The party arrive on the edge of a vast crater in the middle of Acryn. All that is left of the college are the pair of double doors. The Grand Octopus immediately declares itself king of said doors. Lionel, shellshocked, holds Lasarti's broken arm, while Hardy contemplates their newly anomalous nature. Viola is arrested by the Watch, who predictably gathered around the crater after the entire college disappeared. The mages explain what the party did, but recommend they not be arrested, since they did at least attempt to right their wrong. Even so, the Watch are not inclined to look on them favourably. Viola is executed on Corlo's orders – it's done very fast, too, as if something made the Watch feel they had a deadline to meet…
The party hear that something splashed into the bay a few minutes before they reappered. Rowing out there, they find a unified patch of water with a bag resting on it – inside is a thank you note from Ishvala, in which it promises to come back soon and 're-engineer' the world. It also gives them a spark of potential, which will allow them to create a lifeform of some sort. After much disagreement, the party agree to keep hold of it. The Grand Octopus thinks they should use it to make a super-ensouled animal. Hardy thinks this is highly irresponsible. The party hide out at the King's Head, which some silly bugger has dropped into double flux. The Orb floats around the outside of the pub, still booping quietly. Jeremy fixes his face and retrieves a body for Coll to merge with. Lionel looks over Ashel's notes and learns the rite of refinement. The group agree to be Coll's four dads (Lionel, Jeremy, Hardy, and the Grand Octopus). The Dissolver is not happy about how unified the group is.