The Underworld will be a catalyst to a whole new world for our heroes on ABC's Once Upon a Time.

Will Peter Pan's Return To 'Once Upon a Time' Cast Him In 'A Different Light'?

Emma (Jennifer Morrison) and the rest of the gang will search the Underworld for Hook (Colin O'Donoghue) in the second half of season 5. But as Once Upon a Time co-creator Adam Horowitz told TVLine recently, this will just be the beginning of their journey.

"That impetus is the tip of the iceberg," Horowitz noted. "That's just our entry way to another world and a wealth of stories that impact all our characters."

ABC President Suggests 'Once Upon a Time' Renewal Sure To Come?

Emma "comes to terms with the fact that her role as Savior is just beginning," while Snow (Ginnifer Goodwin) and Charming (Josh Dallas) will discover there are "consequences to their headstrong jump to the Underworld, leaving a child behind."

Meanwhile, Regina (Lana Parrilla) is set to have an "interesting" reunion with her mother, Cora (Barbara Hershey).

While a lot of time is expected to be spent in the Underworld, fans will also get to see what others are up to. The TVLine report says that Belle (Emilie de Ravin), who is still in Storybrooke, "becomes very involved" in the main arc, in addition to Zelena (Rebecca Mader).

And as previously reported, Hades (Greg Germann) will have a surprising connection to one of the Once regulars. It sounds like there will be a lot of story arcs in the second half of the season; it remains to be seen if fans will be receptive to them.

Once Upon a Time returns for the second half of season 5 on Sunday, March 6 at 8 p.m. ET/PT on ABC.

Tags: Once Upon A Time television ABC