Belle asks for help to protect her child from the god of the Underworld in the upcoming episode 17, titled "Her Handsome Hero," on the fifth season of the fantasy drama, "Once Upon a Time."

The official synopsis from Disney ABC Press reveals that Rumplestiltskin gets a request from Belle to find a way to protect their child from Hades. Their plans will hit a rough patch, but Belle does not want Rumple to use dark magic so he can use it for evil. Their current biggest opponent, Hades, arranges a secret meeting with Gaston in his territory. The controller of the Underworld convinces the Prince from "Frozen" to seek revenge on Rumple.

The synopsis further reveals that the rest of the heroes are still figuring something out so they can devise a plan that could destroy Hades. Meanwhile, Emma begins to realize that her terrifying nightmare is slowly becoming a reality. Belle and Gaston's past will also be revealed in flashbacks. It will show both of them meeting for the first time, and when their budding romance was about to bloom fully, it was ruined by the war of the Ogres.

A sneak peek of Gaston can be seen on the promo trailer for "Her Handsome Hero." The short clip reveals the characters that the heroes never knew they'd meet in the underworld. Hades visits Gaston and asks the latter if he wants to finally get a shot at revenge. It shows that Rumple was the one who killed Gaston, and when they finally meet again in the Underworld, Gaston tells Rumple that he will return the favor of killing him. When Belle and Hades meet, he tells her that he wants to get her baby.

Meanwhile, here is the rundown of the previous episode. Zelena tried to stop Hades from using Regena to create a time-travel portal even though she has feelings for him. Henry saw visions that have something to do with him.

"Once Upon a Time" season 5 airs every Sunday at 8 p.m. on ABC.