Plot summary
After a prisoner is sent by Hook to tell Emma that he is alive, a creature known as Cerberus begins pursuing the outsiders. This prompts Mary Margaret to turn to the only person who can defeat the creature, Hercules, as she learns that he has unfinished business and is therefore in the Underworld. Back in the Enchanted Forest, he was responsible for giving her the courage to fight back against the Evil Queen's bandits. When the outsiders learn that he has lost that confidence, Mary Margaret decides it's time for him to restore it as they square off against Cerberus and, with the help of the prisoner, kill the creature, giving Hercules and the prisoner, revealed to be Megara, their tickets out.
In the process, Regina convinces Mary Margaret to again become Snow White, the woman who took risks before the original curse. A furious Hades vows to make the outsiders pay by forcing Hook to choose which living souls will stay behind as recompense for the souls they've redeemed. Meanwhile, Henry encounters Cruella, who wants him, in his role as The Author, to resurrect and return her to the world of the living, so that Emma's soul will no longer be branded a murderer's, but he keeps this offer to himself.
Credits
Adapted from Wikipedia contributors, Once Upon a Time season 5. HTML formatting and reference markers removed.