Emma (Jennifer Morrison) and Hook/Killian (Colin O'Donoghue) will not be the only ones to reunite in the Underworld in the back half of "Once Upon a Time" season 5.

The showrunners of the long-running ABC series have teased that there would be a lot of dead characters who would reappear when Emma takes the difficult journey to Hell to save her one true love. During the midseason finale, Hook sacrificed himself to purge the town of all the Darkness, even those inside him and Emma. It turned out that Rumpel/Mr. Gold (Robert Carlyle) double crossed him. This was to ensure that he would be the only remaining Dark One in Storybrooke.

When Emma learned of the betrayal, she forced Gold to accompany her in the Underworld and bring back Hook. If not, Belle (Emilie de Ravin) would learn of what he did. The second half of the installment is expected to show exactly what will happen to them once they reach Hell, and which dead characters they would see along the way. One notable name on the list that fans are curious to see is Gold's ex-wife, Milah (Rachel Shelley).

Gold killed Milah back in season 2 when she ran away with Hook. She and Gold were happily married and living in the forest with their son when he said he had to go and enlist in the ogre war. Milah supported her husband's decision, but rumors of him deserting the other soldiers reached their little cottage. When Gold returned, he admitted that the gossips were true. Milah got so angry, she purposely stayed away from him by going in a bar. That was where she met Hook and they quickly fell in love. Later on, the pair ran away together, leaving Gold to care for their son by himself.

Co-creator Adam Horowitz talked about the possible reunion between the former couple to TV Line. Her "big connection to two of our main characters" would reportedly be an interesting storyline to pursue, especially when she meets Emma, her old lover's new love. Emma was also the wife of their son Baelfire/ Neal (Michael Raymond-James). This interesting bit of family complication will hopefully be tackled in season 5B.

Speaking of Neal, showrunner Edward Kitsis hinted in a recent interview that Emma would be meeting her dead husband in the Underworld. He died in her arms back in season 3 finale, after making peace with each other. Neal was the father of Emma's son, Henry (Jared Gilmore).

"Once Upon a Time" season 5 will return on March 6 at 8 p.m. EST on ABC.