A mysterious female assassin breaks into a S.H.I.E.L.D.. facility, finding and downloading files pertaining to the X-Men but searches for one in particular: Wolverine. After she leaves the facility, she attacks the X-Mansion, knocking out the X-Men one by one. Wolverine finds out that the assassin is his clone, designation "X-23", created by the Dr. Deborah Risman and raised without love to be a living weapon exploited by HYDRA, and that she wants to kill him because she holds him responsible for her miserable existence. Wolverine and X-23 square off in a battle that Wolverine does not want to win.