This Sunday's new episode of Once Upon a Time will be all about disappearances and first appearances.

In the following sneak peek at "Selfless, Brave and True," we see Regina reunite with an old friend, attempting to intimidate Owen by telling him his father has simple vanished. But can that really happen?

Elsewhere, Neal will break some troubling news to Emma: Tamara is on her way to Storybrooke. And if she sees a giant? Or other signs of magic and fairy tale characters? Well... ummm... yeah, Neal may not have thought this plan all the way through.

Finally, Marco will make a major admission to Emma and Mary Margaret. But his reveal isn't the most interesting aspect of the following clip. No, that would be the reaction of Mary Margaret. Watch now to see what we mean and visit our Once Upon a Time spoilers section for still images from the installment:

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.