Adam Darvin and Kerri Ross have finally learned the truth about ACS, the organization attempting to destroy Adam's and Kerri's world. Adam is now desperate to rescue Kerri from ACS and ACS leader Javier's clutches. With his friend Liam Clover and the ACS 5th Columnist Tony Jackson, Adam leads a rescue mission to save Kerri and Tony's imprisoned allies. Meanwhile, Kerri is hardly content to sit and wait for a rescue. She faces off against ACS's leader and attempts to battle her own way to freedom. Soon Adam and Kerri are reunited behind enemy lines. They find themselves not only fighting together to escape ACS, but also leading an unlikely alliance of altereds, interplanetary champions, and kids from Clarendon Ditch. Adam, Kerri, and Liam continue to develop their powers and friendships as they come to terms with their roles in their new world and the war they now must join. The characters grow as they band together to cope with tragedy and battle a new threat that emerges from within ACS. The Alliance continues the series themes of heroism, sacrifice, loneliness, leadership, and friendship with its more serious and darker tone. The scope of the action expands and the intensity of the relationships between the characters deepens. The heroes soon learn that all they have is each other, and together, they might just be all that stands in the way of ACS taking over the world. Will they be enough?