Hook is set to see his brother in the Underworld while Cruella is set to have her moment with David in "Once Upon A Time" season 5 episode 15.

"Once Upon A Time" season 5 episode 15 is entitled "The Brothers Jones." According to Spoilers Guide, Hook will be surprised to see that his old brother is also in the underworld. As per the publication, they are set to look for the storybook that will aid them take down the Underworld god, Hades.

Episode 15 will also see the reunion of Hook and Emma and they are going to find a way to defeat Hades, so they can go back to Storybrooke, along with Gold, Henry, Robin, Regina, Snow, and David.

In addition, Liam, Hook's departed brother, is set to have a surprise visit and guide him to the book that they were looking for. As per the publication, others have also tried to take down Hades, mentioning the book that has they key to his defeat. Then, Henry is set to do things on his own while the others try to find the book.

As for Hades, the god of the Underworld makes an effort to manipulate the heroes in his realm; this is by playing them against one another. A flashback also saw a developing bond between two young Jones brothers when they were tested and empowered on a merchant vessel going to a tumultuous storm.

In other news, Cruella and David are set to have some moments together. According to TV Line, the event will not be a romantic experience for David, as he will be forced to pretend as his brother James when Cruella visited her love interest in the sheriff's office in Underworld. As per the publication, David and Snow are set to check James' desk before Cruella comes.

"Once Upon A Time" season 5 episode 15, "The Brothers Jones," is set to air on Mar. 27.