Nolan's pretty concerned about his daughter - she stole a terrasphere from the E-Rep HQ, and that's totally a gateway weapon to - no, that's the worst kind of weapon; knives were probably the gateway.
And speaking of "gateway," did you hear Treasure Doll was thrown off of the Gateway Arch? (Barely noticed that segue, huh?) Nolan doesn't have time to investigate, so he deputizes Amanda (she pretty much deputizes herself, but whatevs). She teams up with Berlin, and in no time, they learn that Alak was chupping his employee, and had threatened to throw her off the arch if she made trouble (Treasure Doll was a pretty smart cookie - she recorded all of her conversations and "conversations" with Alak, in case she might need to blackmail him in the future.)
Alak winds up in jail and Christie, who's already upset that her father's in prison after confessing to killing Olfin Tennety, freaks out. Stahma thinks Datak killed the DJ-prostitute (everyone's got a hyphen these days, sheesh!) but Datak assumed Stahma did it! Hmm... then who put the bloody microphone that killed Treasure Doll under Alak's bed? Stahma laughs and laughs when she realizes that her enterprising daughter-in-law is really getting the hang of putting family first - it was Christie that done it! Stahma's relieved that the man she convinced to take the fall for the murder - a terminally ill Casti whose daughter gets to be a Tarr handmaiden in return for his confession - is still going to help their family, just not in the way she expected.
Christie tells her sweet, philandering husband the whole thing: Treasure Doll tried to poison her - or, more accurately, served her juice containing poison that would've killed their baby - so she had to take that biotch OUT. Christie doesn't mind, this one time, but if Alak ever puts their family in jeopardy again, she'll probably chop his babymaker off. Seems like Christie's time at that dress-up club really changed her...
But what of Irisa's plan to destroy the world? It's going pretty well, thanks for asking! Nolan discovered Tommy at Irisa's compound, but because Tommy's human, his body rejected all those gross tendrils that puppet Irisa and her crew. Tommy keeps up his cover long enough to help Nolan plant small devices that scramble the functioning of the arkbrain (the tech that's controlling Irisa and her minions), incapacitate the camp, and steal Irisa away.
But arkbrain is wily. Just as Tommy and Nolan are driving back to Defiance with a comatose Irisa in the back seat, she wakes, kills the roller's engine, knocks out Nolan, and stabs Tommy. She then absconds to her camp above the Kaziri (the giant spaceship that will rise from the ground, kill all humans, and leave Earth for the Votans). Nolan wakes to find his daughter lost - again - and Tommy mortally wounded. Without a working roller, Nolan has to drag his friend back to town, and pray that he doesn't die along the way.