In a Camelot flashback, Hook becomes a Dark One and his lust for revenge against Rumplestiltskin is reignited. When Emma and Hook disagree about their best course of action, the final pieces of the puzzle are revealed as events in Camelot catch up to the present and we witness a charged confrontation between the forces of light and dark that sends our heroes on a collision course with destiny. Meanwhile, in Storybrooke, Hook’s centuries old lust for revenge against Gold puts both of their fates in jeopardy while Emma’s love faces the ultimate test as she tries to convince Hook to turn away from the darkness before she, Mary Margaret, David and Regina embark on a new mission as an unsuspected evil is released.