Poor Unfortunate Soul

"Poor Unfortunate Soul" is is the sixteenth episode of the fourth season of the American fantasy drama series Once Upon a Time, which aired on March 22, 2015.

Plot
As the heroes attempt to rescue August from Gold and the Queens of Darkness in their quest to track down the Author, Hook finds a way to make a deal with Ursula to get the information he needs to help the heroes as a way to make up for what he did back in the past, in which Hook made a deal with Ursula's father Poseidon that led to unfortunate consequences for both Hook and a young Ursula.

Trivia

 * The episode is named after a song from the The Little Mermaid.
 * Ursula sings "Part of Your World" and "Fathoms Below" from The Little Mermaid during the episode.