A mysterious female assassin terrorizes the X-Mansion, knocking out the X-Men one by one. Wolverine finds out that it is his clone, created by the Dr. Deborah Risman and raised without love by HYDRA, and she wants to kill him because she holds him responsible for her miserable life. Wolverine and X-23, as she is called, square off in a battle that Wolverine does not want to win.