The heroes of Storybrooke will continue their journey to get out of the Underworld in the next episode of "Once Upon a Time" season 5.

The episode, titled "Our Decay," features the importance of family for the Storybrooke heroes. According to the synopsis, Rumplestiltskin (Robert Carlyle) will make an agreement with the Underworld lord, Hades (Greg Germann), to create a portal that will allow Belle (Emilie de Ravin), their child, and Zelena (Rebecca Mader) to pass through the sinister version of Storybrooke. But instead of a happy reunion, Belle and Rumplestiltskin's relationship will once again be tested after he reveals shocking news to the mother of his child.

Meanwhile, Zelena's visit to the Underworld will reunite her with Hades. Based on the promo trailer for the episode, the two seem to have had a romantic relationship in the past. Does it mean that the ruthless leader of the Underworld is also the father of Zelena's child?

Meanwhile, Snow White (Ginnifer Goodwin) and Prince Charming (Josh Dallas) will also think about their son Neal (Michael Raymond-James), who was left in Storybrooke when they decided to join their other child Emma (Jennifer Morrison) on her journey to the Underworld to look for Hook (Colin O'Donoghue).

In an interview with TVLine, Dallas revealed that the Charmings will try to do everything that they can to be reunited with Neal.

"They don't want to make a mistake like they did the first time with Emma," the actor said. "So now that they've left Neal, they've got to try to get back to him."

Series co-creator Adam Horowitz also talked about the dilemma of the Charmings because of their leaving Neal behind.

"There certainly are consequences to that sort of headstrong jump into the Underworld, where they left a child behind. There are some really emotional things they're going to have to deal with because of that," Horowitz said in the same report.

"Once Upon a Time" season 5 episode 16 airs on Sunday, April 3, on ABC.