The map is bidirectional, and the purple dots are coming. It's Lolth and her pit fiend against Kas and Myska, with Vecna somewhere behind it all. Vae's sister Nixa stays behind while we go to find out what's in the room the demons won't stop talking about. It smells like blood.
The missing Pieces of the Rod of Seven Parts sit in crystal cases around a cracked arcane globe: the Sphere of Law, which holds Myska bound. Gnarls and Jain go invisible, Jain only staying hidden thanks to Gnarls' bardic inspiration, and Fell plucks the first Piece out with a mage hand. Then the second. The demons notice the first is gone, and freak out.
The ritual pool boils with oil, and a face of enormous evil rises from the orb. Then Illustrial Silverhand is simply standing next to Gnarls, asking what's going on. Jain shouts that she's a fake, an illusion, a witch. Jain is, it turns out, right. But we don't know that until later.
Myska roars, a psychic blast that hits us all, and hauls himself out of the shaft. He is enormous. He hurls five evil orbs at Fell, drags a Piece back into its case, and the Sphere cracks above it. Gnarls tries to polymorph him. Nothing.
Jain bursts out her wings. Hasted, she cuts down a wounded demon, flies to the case, wrestles the Piece out, and is over the blood ring before anyone can stop her. Fell blinks over to hand her his Piece too.
Kas is here, and Illustrial is gone; it was probably him all along. Sugar shakes off Myska's suggestion, and the Hand of Vecna smashes the blood ring. Gnarls polymorphs the last demon into an octopus, which falls thirty feet with a splat, then plays Spirit Guardians at 9th level straight into Kas. But Kas keeps putting the Pieces back.
Kas is somehow still standing and Myska's voice is still in our heads, insisting it would be best to put the Pieces back. It's Fell's turn. The battle rages on!