Two exceptional students face their ultimate test when they answer a call for help, in the first suspense novel from Xavier's Institute, focusing on the daring exploits of Marvel's mutant heroes. As part of their training at the New Charles Xavier Institute, Triage and Tempus are allowed to attempt their first solo flight mission. Somehow into their mission they receive an urgent SOS message: Sentinels attack a super-powered mutant, who is struggling to protect a wounded politician. However, when they abandon their lessons and answer the call, the identities of both will cause the two young X-Men much more trouble than they expected.