Colin O'Donoghue, <em>Once Upon a Time</em> Colin O'Donoghue, Once Upon a Time

[WARNING: The following contains spoilers from Sunday episode of Once Upon a Time. Read at your own risk!]

Once Upon a Time is not known for its subtlety or restraint, and Sunday's episode multiplied our heroes' danger by literally shipping a boatload of trouble into Storybrooke.

Now that Killian Jones' (Colin-O'Donoghue) Dark One persona has been unleashed, he's gone fully dark with a vengeance. This show is usually about revenge for some past hurt after all. For Hook, the object of his revenge is Rumplestiltskin (Robert Carlyle), who wreaked his own havoc back when he was a Dark One.

Here's a breakdown of what went down in the episode:

Good News

Zelena didn't kill anyone (this time): In fact, Zelena (Rebecca Mader) was positively sweet while cooing to her daughter, the infant only known with the working title "Baby Hood" for now. We're sure the naming of said kid will honor some dead person, but that's to be saved for another episode. Since Regina (Lana Parrilla) felt she was "saved" by her son Henry (Jared Gilmore), she's betting that Baby Hood will somehow redeem her murderous mom. Zelena also wins for the best line of the night: "Once you go green, you'll never go queen."

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Henry and Emma are reunited: Henry was not pleased that his bio mom Emma (Jennifer Morrison) lied to him and made his Camelot sweetheart break his heart. But after some groveling and asking for his help, Emma earned back his trust (so easy!), and before you knew it, Operation Cobra Part 2 was underway. Again, Once got a little lazy with the naming of this episode.

Bad News

Rumbelle fans got slapped down: Although Rumple is now pure of heart and has proven his heroism twice over, it's too late. Belle (Emilie de Ravin) has just been hurt by him far too many times. "I've spent too many years trying to mend your heart; now I need to protect mine," she said, shattering his heart. Although we're sure they'll somehow be reunited, it will be fun to see Belle actually strike out on her own for a bit.

We know who killed Merlin: Sadly, the wizard became Dark Hook's first victim back in the Enchanted Forest in order to create the key ingredient for the curse that would return the gang to Storybrooke present. Poor Merlin (Elliot Knight) has had a lousy season: His love became the first Dark One, he got magicked into a tree for years, and no sooner is he back than his heart gets crushed.

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Worse News

Send in the Dark Ones: Why bring in only one new Dark One when you can bring in a whole shipload of them from Hell? That, not just revenge against Rumple, was Dark Hook's plan all along. He just needed Rumple's blood -- the blood of a person who's been to Hell and back -- to open the portal to the underworld. How will our heroes possibly defeat a horde of Dark Ones? Well, this is all a set-up for next week's winter finale, which leads into the second half of the season, which we've already learned will be "Hell"and will bring back many deceased villains. Perhaps Emma & Co. will be fighting evil with evil. Once just can't resist a good redemption story!

What did you think of Dark Hook's plan? Is there hope for Rumple and Belle? Any bets on Baby Hood's name?

Once Upon a Time airs its winter finale on Sunday at 8/7c on ABC.

VIDEO: Once stars share their characters' ultimate happy endings