"Once Upon A Time" Season 3 spoilers reveal the return of The (Little) Mermaid in the Enchanted Forest. OUAT 3x17 has Captain Hook's Jolly Roger, Ariel and Hook himself in the centre of the episode. In present timeline, the Evil Queen plays Emma Swan's mentor to finally beat the Wicked Witch.

Spoiler alert: This feature contains spoilers on Once Upon A Time Season 3, Episode 17 ("The Jolly Roger"). Read at your own risk.

The Evil Queen Regina (Lana Parrilla) confirms the Wicked Witch Zelena (Rebecca Mader) is her half-sister. The latter tries to rip her heart out, but the former knows better. However, in Once Upon A Time Season 3, Episode 16 ("It's Not Easy Being Green"), the Wicked Witch remains undefeated.

The Wicked Witch already has Rumple's "brain" and the "courage" of Prince Charming (Josh Dallas). Rumplestiltskin aka the Dark One (Robert Carlyle) is still Zelena's puppet. Now she wants Regina's heart to complete the collection. But Once Upon A Time Season 3, Episode 17 will probably show less "Regina vs Zelena" to give way to other rich storylines.

Many Oncers are probably wondering: What happened the first time the Wicked Witch met Captain Hook? Watch the promo video for this week's new episode to get a sneak peek into OUAT 3x17, featuring Ariel (JoAnna Garcia Swisher), Zelena, and Captain Hook (Colin O'Donaghue).

How is Captain Hook's lady love, Emma Swan (Jennifer Morrison)? The firstborn of Snow White (Ginnifer Goodwin) has to learn magic from the evil queen. This ABC fantasy series has gone a long way in twisting the classic fairy tales for modern day television. Once Upon A Time Season 3 is expected to bring more surprises as the season finale draws near.

Now how will Regina teach Emma Swan more magic in Once Upon A Time Season 3, Episode 17? The evil queen has taught Emma some magic skills in the past. But now that Baelfire aka Neal (Michael Raymond-James) is dead, the evil queen could tap into Emma's anger to hone her magic. Still, it does not seem likely for Emma Swan to practice dark magic.

The Wicked Witch continues to spread terror in Storybrooke. No one remembers what happened within the year that they could not recover from their memory. Once Upon A Time Season 3, Episode 17 should have more answers than questions.

WATCH: 'Once Upon A Time' Season 3, Episode 17 Promo Video (ABC on YouTube)

Oncers can watch Once Upon A Time Season 3 on ABC Go or On Demand. The next new episode, "Bleeding Through," airs Apr. 20.

More TV Guide and Spoiler Features

'Once Upon A Time' Season 3 Spoilers, Teasers from Creators: Is [SPOILERS] Really Dead? Wicked Witch vs the Evil Queen Power Face-Off! [Watch Promo Video]
'The Good Wife' Season 5, Episode 17, 'Material World' Spoilers: Josh Charles Reveals Reasons for [SPOILERS]; Firms Merging into Season 6? [Watch Promo Video]
'Game of Thrones' Season 4, Episode 1 Spoilers: Watch Promo Videos, Daenerys Targaryen and the 'New Daario Naharis' [TRAILERS]