Wolverine. Sabretooth. Silver Fox. Wraith. Maverick. Together, they were Team X, the best covert-ops team NATO had to offer. But a mission to retrieve a disk from a pair of Soviet agents proved to be more trouble than they bargained for. A Soviet operative codenamed the Black Widow, a mutant Interpol Officer named Sean Cassidy, and shape-changing freelance spy Mystique were also all after the disk.

Years later, Wolverine is a valued member of the uncanny X-Men. The Black Widow defected and became a respected American super hero. Cassidy is Banshee, mentor to the next generation of young mutants. Mystique and Sabretooth are reluctant members of X-Factor, the government strike force. Wraith is still a covert-ops agent. Silver Fox is dead, and Maverick is dying of the Legacy Virus.

Each of them is kidnapped, one by one—starting with Sabretooth, by far the deadliest member of the former Team X. Wolverine must find out the terrible secret from that old mission—a secret that has remained hidden for years and could spell death for all of them!