Will the “Once Upon a Time” characters get a happy ending in the Season 5 midseason finale? That’s up in the air right now as the Dark Ones take over Storybrooke on the ABC fairytale drama.

On Sunday, the heroes will have to face years of evil thanks to Dark Hook (Colin O’Donoghue) resurrecting the Dark Ones from the underworld. But based on the synopsis for episode 11, titled “Swan Song,” it doesn’t sound like anyone in town has much hope to survive them snuffing out the light.

According to the episode description, the Dark Ones must “target a living soul for sacrifice so that they can return to the realm of the living.” But who will their target be?

Gold (Robert Carlyle) knows there is no way to stop them, and instead of fighting, encourages the others to “spend their last fleeting moments enjoying the company of their loved ones.” But that doesn’t mean everyone is ready to give up. Emma (Jennifer Morrison) understands that she’s responsible for everything happening right now and is prepared to keep fighting. There is one problem though – she must face Hook.

“When they face off with the fate of Storybooke at stake, Hook’s actions will devastate Emma in a way no one saw coming,” the midseason finale synopsis continues.

Meanwhile, “Once Upon a Time” fans will get another look into Hook’s past thanks to a flashback. In the flashback, the Evil Queen (Lana Parrilla) forces Hook to confront a “demon from his past” in order to test him. If Hook passes, he’ll have to “dispatch one from hers.”

The “Once Upon a Time” Season 5 midseason finale will air on ABC Sunday, Dec. 6 at 8:15 p.m. EST. The episode will be delayed because of the president's speech. Watch sneak peek videos of episode 11 below: