Emily's plan is in danger of collapsing on "Revenge."

In Sunday's episode, "Surrender," Lydia (Amber Valletta) returned, to the shock of everyone, because it was believed she had died in a plane crash. She thanks Victoria (Madeleine Stowe) for getting her off that plane, and chalks it up to "a momentary lapse of evil."

Daniel (Joshua Bowman) tells Emily (Emily VanCamp) to keep her pregnancy a secret, because if Voulez catches wind of it, it would "throw the issue into chaos." He also tells Sarah (Annabelle Stephenson) that he can't call off the wedding because the magazine needs to cover the event to boost its sales. Later, Sarah gives back a necklace, which was a gift from Daniel. This infuriates Daniel, who throws it into the ocean. He says that he is now committed to Emily and their "baby."

However, Emily is not very committed to him. Aiden (Barry Sloane) secretly proposes to Emily, and Emily readily accepts. The duo also plans for her imminent "death." They even put gunpowder on one of Victoria's bracelets and have passports that will allow them to pass for Nolan's (Gabriel Mann) distant cousins.

Lydia also gets back into bed with Conrad (Henry Czerny), and while there, she discovers photo albums that reveal Emily has been stalking the Graysons for years.

At episode's end, Daniel tells off Victoria for meddling, which prompts Victoria to hand her RSVP card back to Emily, saying she will not attend the wedding.

On the upcoming midseason finale, "Exodus, "The wedding of the century has finally arrived and Emily's master plan will be poised to go off without a hitch until enemies unite, bringing new complications and leading to dire consequences."

TVLine also released a series of photos from the upcoming wedding, which you can check out here.

On the upcoming episode, there will also be two romantic reunions, a nice moment between Emily and Jack, awkward run-ins, and a shooting.

Watch the promo for "Exodus" below, which airs Sunday, Dec. 15 at 9 p.m. EST.