Emma, David and Mr. Gold must protect Mary Margaret against Regina, who is out for revenge and has made it her mission to kill her old nemesis, and Henry, fed up with all of the feuding, devises a plan to put an end to magic. Meanwhile, Regina discovers that a father and son have somehow found their way into her allegedly undetectable town as she and the fairytale characters deal with the effects of the newly cast curse 28 years prior.