When "Once Upon a Time" returns on ABC with season 5, it will focus on Emma Swan (Jennifer Morrison), Henry (Jared S Gilmore), Captain Hook (Colin O'Donoghue), Evil Queen Regina Mills (Lana Parrilla), Robin Hood (Sean Maguire), Lily (Agnes Bruckner), Wicked Witch aka Zelena (Rebecca Mader), Belle aka Lacey (Emilie de Ravin), Mr Gold aka Rumplestiltskin (Robert Carlyle), Prince Charming aka David Nolan (Josh Dallas) and Snow White.
After taking viewers through a new fairytale world created by The Author (Patrick Fischler) that showed villians getting their happy ending and heroes suffering, the series introduced them to the new author, and it is none other than the son of the Saviour of Enchanted Forest. He managed to bring out the characters of Storybrooke to the world created by Fischler's character.
Although the young writer had the power to give happy ending to his loved one's, he decided to break the pen and said, "No one should have that much power" in the finale of season 4. Immediately after that, Gilmore's character and his family faced a new danger. After the darkness was taken out of Mr Gold's body, it started looking for another human body. When it tried to devour Regina, Emma saved her by sacrificing her life.
So the upcoming season of ABC series is expected to revolve around the darker side of the Saviour. There are only two ways to control the darkness and that is either to find Merlin aka the Sorcerer or hold the dagger.
Since Henry has already showed the courage to enter a fairytale world and save his family, it can be assumed that he will team up with Hook to find the character. Meanwhile, Regina, Pince Charming or Mary Margaret may hold the dagger to control Dark Swan.