As Regina (Lana Parrilla) mourns the loss of her poor Robin (Sean Maguire), at least one ship is sailing strong on "Once Upon a Time."

Hook's (Colin O'Donoghue) miraculous return to Storybrooke from the Underworld has turned Emma (Jennifer Morrison) back into the joyful hero she used to be, but in this latest sneak peek, not everyone is happy to see him alive.

It's not a new issue between Henry's warring mothers that Emma always seems to come out on top, while Regina gets the short end of the stick more often than not. This latest revelation that Emma's love was spared from death, while Regina's was sentenced to oblivion will most likely not go over well between the two ladies.

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Amid all the drama, we've also got to worry about what new catastrophe has struck the town, in the form of what appear to be magical lightning bolts raining down from the sky.

Has Rumplestiltskin (Robert Carlyle) done something terrible with that Olympian Crystal? Will Regina be a be able to resist the dark impulses of her Evil Queen side? Find out in the Season 5 finale.

The "Once Upon a Time" season finale airs Sunday at 7 p.m. ET/PT on ABC.

Posted by:Lindsay MacDonald

Lindsay MacDonald is a Los Angeles based entertainment reporter with an affinity for CW superheroes. She graduated from Pepperdine University with a major in Media Studies and a borderline unhealthy obsession with TV in 2012. She would much rather spend the day binge-watching ‘The Flash’ or sorting ‘Game of Thrones’ characters into Hogwarts houses than venturing outdoors. TV words to live by: “Never ignore coincidence. Unless, of course, you’re busy. In which case, always ignore coincidence.”