All eight episodes from the first season of the sci-fi thriller based on the Marvel Comics character Legion. David Haller (Dan Stevens) was diagnosed as a young boy with schizophrenia and spent his life in psychiatric hospitals. While a patient at Clockworks Hospital, David has an encounter with Sydney Barrett (Rachel Keller), a young girl with mutant powers, who suggests to him that he might not actually be ill; he might be a mutant. As government agents interrogate him to find out who he really is, David battles with the reality that he could be the most powerful mutant who ever lived.