With Star City in peril from a new gang, Laurel and Thea go behind Diggle's back and ask Oliver and Felicity to come back to help them.
A missing pregnant girl reappears after eight months, and dies of exposure. The doctors save her child, and Liv takes on a strong maternal instinct after eating the girls' brains. Meanwhile, Major follows Julien and learns about his interest in brains.moreless
Castiel calls on the Winchesters to help when his army of angel followers are attacked, and Dean is all too eager to help under the First Blade's influence.
Bolivia and her team call upon their counterparts from This Side for help when a serial killer goes on a bloody rampage. They recruit the killer's This Side counterpart, a professor of forensic psychology, and try to transfer him to the Other Side without his knowledge to put together a profile on his other self. However, things soon go out of control when the professor realizes what's going on.moreless
Henry's old captain believes he's solved a murder, but his Alzheimer's has caused him to forget the most important details: the crime, and who committed it. Henry calls in Shawn and Gus who find themselves investigating a murder that happened decades ago – or was it just the other day? – and only the faulty memory of the retired officer gives them any hope of closing the case.moreless