Psychiatrist Dr Abhiri Chatterjee receives a phone call in the middle of the night. The caller, who wants to commit suicide, is also a murderer on the loose — or so it appears.
Federal agent Alexandra Barnes believes that Catherine Petersen is a serial killer who marries rich men and then murders them for their money. But since Catherine is seemingly a master of disguise and has multiple identities, Alexandra can't prove anything with conventional detective work. With no other option, she goes undercover, pursuing the same man as Catherine, and hoping that Catherine will slip up and reveal her true identity.
An Oxford Medical School graduate takes a position at a mental institution and soon becomes obsessed with a female mental patient, but he has no idea of a recent and horrifying staffing change.
Fresh out of prison, Ava's attempt to reclaim her drug operation collapses when she witnesses a brutal crime, forcing her to flee into a nightmarish underworld where allies are scarce and enemies multiply by the minute.