'Once Upon a Time' season 6 episode 12 spoilers: Why does Gideon want Emma dead?

Gideon's (Giles Matthey) motivation for wanting to kill Emma was finally revealed in the mid-season premiere of "Once Upon a Time," which aired on March 5. He told his parents, Belle (Emilie de Ravin) and Rumplestiltskin (Robert Carlyle), that he needs her dead so he can get her powers as a Savior to free the residents of the dark realm, where he was raised by the Black Fairy.

Gideon discovered, however, that killing Emma was not that easy, as she was able to fight back and defeat her assassin, although she lost her sword in the process. "Once Upon a Time" series co-creator Adam Horowitz, however, warned that this was just the start of the fight between the two.

"We can expect another showdown," he said to TVLine. However, his fellow show creator, Eddy Kitsis, said in the same interview that this can also provide the opportunity for Rumplestiltskin and Belle to renew their relationship. Even so, Gideon will put the Charmings and Emma to one side of the fence and the estranged couple on the other.

Meanwhile, Regina (Lana Parrilla) was able to convince the Wish Realm incarnation of Robin Hood (Sean Maguire) to join her and Emma as they returned to Storybrooke. However, Kitsis, in an interview with TV Guide, said that there was something more to this. He said, "What we can tell you is that if people think we just brought Robin back, he's the same person, and we're just like, 'Oh, he's coming back to the show!' – that's not what's happening. It's a new story. It's a different Robin."

Next week's "Once Upon a Time" episode, titled "Murder Most Foul," is set to delve into this further. The episode will see this Robin adjusting to his new life in Storybrooke, even as Regina will discover something dark about him.

"Murder Most Foul" is also set to put two unlikely characters together — Captain Hook (Colin O'Donoghue) and David (Josh Dallas) — who will discover who killed David's father.

Season 6's episode 12 will be shown on March 12, Sunday, at 8 p.m. ET on the ABC.