S2·E10 Grey Matters

The First Wave breaks into a mental hospital and cures a long-term patient suffering from schizophrenia. When the Fringe team investigates, Olivia discovers that the group's leader has one of the heads stolen from cryogenic storage months earlier. Meanwhile, two other mental patients are cured of their schizophrenia and the team soon realize that something was taken from each patients' brain... and Walter holds the key to realizing what First Wave is after.