After Mr. Gold's house is robbed, Emma keeps a close eye on him when it looks like he wants to track down the criminal and dole out some vigilante justice as payback, and Valentine's Day finds Mary Margaret, Ruby and Ashley having a girls' night out. Meanwhile, in the fairytale land that was, Belle agrees to a fateful deal to give up her freedom in order to save her town from the horrors of the Ogre war.

Belle threatens to leave Mr. Gold if he doesn't change his ways; the dwarves try to find fairy dust in the Storybrooke mine; Rumplestilskin tries to save his wife from a band of pirates.

Hook and Emma try to find their way back to the present and correct the mistakes they made in the past.

The race is on to track down the elusive Snow Queen in order to discover what her ultimate end game is for Elsa and the residents of Storybrooke. Unaware that she does not possess the real blade that controls The Dark One, Belle attempts to use it to get her reluctant husband to show her where the Snow Queen is hiding. Belle travels to Arendelle and, with Anna's help, seeks out Grand Pabbie to help her regain her lost memories in order to discover the fate of her mother.

The dark siege of Storybrooke is underway as all of the resurrected Dark Ones target a living soul for sacrifice so that they can return to the realm of the living. With doom imminent, Gold advises Mary Margaret, David and the rest of the heroes to spend their last fleeting moments enjoying the company of their loved ones. Emma, however, refuses to give up, knowing that she is responsible for righting all the poor choices she made as Dark One - there's only one problem, Dark Hook. When they face-off with the fate of Storybrooke at stake, Hook's actions will devastate Emma in a way no one saw coming. In a Fairy Tale Land flashback, the Evil Queen tests Hook's mettle by forcing him to confront a demon from his past before contracting him to dispatch one from hers.

Belle turns to Rumplestiltskin with hope of finding a way to protect their child from Hades. However, they disagree over whether to use dark magic, as Belle forbids Rumplestiltskin from using his powers for evil. Meanwhile, Hades secretly meets with Gaston in the Underworld and encourages him to seek revenge on Rumplestiltskin. As the heroes try to find a way to defeat Hades, Emma has a terrifying nightmare that she realizes is beginning to come true. And in flashbacks, Belle and Gaston meet for the first time, but their blossoming romance comes to a halt on the eve of the Ogre wars.

Emma, David, Regina, Robin and Henry are finally back home in Storybrooke and reunited with Snow, but, unfortunately, they still have to contend with Hades, who continues to deceive Zelena as he lays out his plan to use the all-powerful Olympian Crystal to take over the town. The heroes desperately search for a way to defeat Hades while Hook does the same in the Underworld, looking for those missing storybook pages. Regina and Robin take a more direct approach, which culminates in an epic showdown that will leave our heroes forever changed.