Scott and Malia go to Peter for answers as to why Derek is suddenly a teenager. Later he is in his family's vault when a mysterious figure steals $117 million in bearer bonds.
Although he didn't want to, Peter agrees to pay Braeden to find Kate. He hopes that Kate can lead them to the person that robbed the Hale Vault.
Peter comes looking for Derek in his loft. Derek isn't there, but The Mute is. The Mute throws a tomahawk at Peter's chest. Peter fights the Mute, even with the tomahawk in his chest. The tomahawk was laced with wolfsbane; the only way to heal it is to burn the cut. Peter later kills the Mute at Beacon Hills High School in front of Derek and Sheriff Stilinski by slashing him to death. Derek says that they have moved on, found better ways than to kill people. Peter claims that he is a creature of habit.
Peter punches Brett Talbot when he runs away. He later finds Kate hiding in the sewers. He offers to teach her control in exchange for the return of his stolen money and (mainly) power.
Peter tries to convince Malia that he isn't a 'bad guy.' He promises to help her find her mother. He is very relieved when he learns that Scott isn't really dead.