In season four, Joe really says a new country, new me. After simulating his death after the murder of Love and fleeing from California to London, he begins to work as a university professor under the aka Jonathan Moore. But he quickly realizes that he cannot escape his past simply because he changes his identity.
While Joe first tries to find Marienne, whom he was obsessed with in season three, he ended up letting her go and moved on. He then turned his attention to a rich woman named Kate (Charlotte Ritchie) and completely concentrates in her circle, trying to connect with her friends and her lifestyle. Not only is Joe entitled by Kate, but he also sees an opportunity to create a new public figure, one with status and power, while he continues to hide his dark past.
However, Joe’s past will always haunt him, even when he does not realize him. Throughout the four season, Joe – as well as viewers – dive more deeply in his psyche and his constant inner battle while he sails in his new identity and his violent tendencies. It also leads Joe to believe at the beginning that there is another killer who teases him with bodies who arise, however, it is in fact a fictitious person in his head, who is a manifestation of his own dark impulses. He finally realizes that he is the one who commits the murders and that his interactions with a man named Rhys Montrose (Ed Speleers) are hallucinations.
During the fourth season, Joe kills several other people, even those for whom he did not realize that he was responsible at the beginning, including Real Rhys Montrose; Malcolm (Stephen Hagan), colleague college professor; Simon (Aidan Cheng), an artist; Vic (Sean Pertwee), Lady Phoebe’s driver and bodyguard; Gemma (Eve Austin), Kate’s friend; Tom Lockwood (Greg Kinnear), Kate’s father; Hugo (Craig McGinlay), the driver of Tom Lockwood; and Edward (Brad Alexander), student of Joe. As for this last death, Joe supervises his other student Nadia (Amy-Leigh Hickman) for the murder of Edward and she goes to prison. Joe also thinks she killed Marienne, however, she escapes.
