'Once Upon a Time' season 6 spoilers, plot news: Emma and Hook's romance challenged by 'A Bitter Draught'? Robin Hood returning to series?

"Once Upon a Time" season 6 premiered last Sunday with the episode titled "The Savior," and it didn't waste time setting the tone for what's to come this installment. The episode featured all the elements that make the series tick—magic, joy, and bittersweet moments.

What's noteworthy about the premiere episode is that the new characters teased before the start of the season haven't made their presence felt yet. The blimp that crashlanded in Storybrooke was there, alright, but its passengers, the likes of which include Aladdin (Deniz Akdeniz), Jafar (Oded Fehr) , and Jasmine (Karen David) were a no-show in the sense that not much focus was given them. Yet.

However, one of the lines Jafar threw in the premiere episode of season 6 probably set the tone for the entire installment. He said, "That's why you never, ever hear these words about a Savior: 'They lived happily ever after.'"

His words might somehow be connected to the vision that Emma (Jennifer Morrison) had, one that showed her brutal death in battle. Nevertheless, she chose to keep it a secret, seeing as how the vision was short of saying there was no way out of Emma's future predicament.

There was focus on Rumbelle, which was poignantly sweet. Rumpelstiltskin (Robert Carlyle) was adamant to get Belle to wake up, but in the dream world where they danced, Belle (Emilie de Ravin) resolved not to take him back as she was aware of her terrible history with him.

On Sunday's episode 2 titled "A Bitter Draught," it looks like Emma and Hook's (Colin O'Donoghue) relationship will take an unexpected turn when a mysterious man from the Land of Untold Stories arrives in Storybrooke. Emma will be busy finding out more about her strange vision while Hook will be hunting for a place for Belle to hide from Rumpelstiltskin.

Snow White (Ginnifer Goodwin), Prince Charming (Josh Dallas), and Regina (Lara Parrilla) will team up to neutralize the threat as the lovebirds are busy with their individual missions. However, according to executive producer Edward Kitsis, Emma's keeping her vision a secret from Hook might take a toll on their relationship.

The synopsis for the upcoming episode reads:

"When a mysterious man from the Land of Untold Stories, who has a past with the Evil Queen, arrives in Storybrooke, David and Snow work together with Regina to neutralize the threat. Belle seeks Hook's help finding a safe place to hide away from her husband, Mr Gold. The Evil Queen continues to try to win Zelena over to her side, while Emma resumes her therapy sessions with Archie and shares her terrifying vision of the future."

In related news, Entertainment Weekly exclusively reports that Sean Maguire will be returning to "Once Upon a Time" season 6 to reprise his role, Robin Hood. It will be recalled that the character met a gruesome end in season 5, but apparently, he will be appearing in multiple episodes in the current installment. As to what capacity he will be appearing in—via flashbacks or other means—remains to be seen.

"Once Upon a Time" season 6 airs Sundays at 8 p.m. ET on ABC.