Fuse begins where Pure, the first novel in the series, left off (see previous blog for summary of that book). Pressia is with Bradwell and El Capitan, while Partridge is with Lyda being protected by the Mothers. They are on the run hiding the vials to help with the cure from Willux. Bradwell has been able to get one of the Black Box machines to become a kind of pet named Fignan, and Fignan gives them facts about anything in the universe they want to know, while also being a secret-keeper with information on how to bring down the Dome and Willux, which they are able to decode by using the names of the Seven. This gives them the information they need to realize they must get to Ireland to a dome located there. Hastings (one of the Special Forces agents) helps them until they are overtaken by Dusts near an amusement park. The kids living inside the park save Hastings, Pressia, El Capitan, and Bradwell, and they turn out to be the very same kids who Bradwell was trying to help escape the OSR's training program.
They figure out that there is an airship located in old world Washington DC in the Capitol building and they steal it to make it overseas to Ireland and the Dome there. They are forced to crash land the plane when a tear gets into one of the air valves. Bradwell stays with El Capitan since he has a concussion from the crash, and Pressia continues alone.
In the meantime, Partridge has turned himself in to the Dome and his father because his father released mechanical type spiders into the wastelands with bombs attached and threatened to kill everyone if he did not return. Once inside, he is kept hostage by his stepmother Mimi and her daughter Iralene, although Iralene eventually helps him escape, where he takes up residence with his former teacher Mr. Glassings to become the leader of the group known as Cygnus to take down his father. Partridge eventually turns himself in to his father in order to get "in the loop" to figure out a way to destroy him. When he turns himself in, his father has Arvin Weed (Partridge's old friend but now the resident surgeon) perform a surgery on Partridge's brain which makes him forget everything that happened outside the Dome during his time in the wastes.
Lyda has chosen to stay behind in the wasteland to live with the mothers since she feels this is what she was destined for. She later discovers that during their one tryst, she has become pregnant with Partridge's child, and when the mothers find out they are adamant that they believe he raped her, since all men are "deaths" and they storm up to the Dome, determined to kill Partridge. Lyda runs to the front so they will stop and is captured by Special Forces and taken to a holding cell. Small bits of Partridge's memory has been coming back to him, and when he sees Lyda in the cell he sends Iralene with a paper snowflake to give to her, to let her know he hasn't forgotten her and he still loves her. Partridge then goes to see his father. Iralene has now told him that his father plans to kill him and have his own mind implanted in Partridge's body, since his own body is disentigrating due to the enhancement drugs (hence why he is after Pressia to try to get the vials and formula to cure himself, but when he realizes he is going to die before he finds her he then chooses to take over Partridge's body).Iralene has given Partridge a poison capsule, and when Partridge pretends to kiss his father goodbye he spits the poison into his dad's mouth.
Meanwhile, after getting into a tangle (no pun intended) with some Evil Dead type vines, Pressia manages to reach the Dome in Ireland and Fignan shows her that he is indeed a key because he opens up a box with the complete formula for the cure in it. Pressia then discovers another scientist at this Dome, who turns out to be one of the original Seven. Since she doesn't know who's side he is on, she runs (finding a horse in the Dome) and goes to find Cap and Bradwell, who are close to death, having become entangled by the evil vines themselves. Pressia cuts them loose but Bradwell is about to die from blood loss from the thorns in the vines, so she injects part of one of the vials into the birds on his back. He is healed, but the birds have morphed into giant wings now, so Bradwell is kind of like a giant butterfly,angel, bird thing with six sets of huge wings sticking out of his back, and the airship is still not fixed so we have no idea how they are going to get back home. END OF BOOK 2