Anthony Mackie and Sebastian Stan attended a recent Wizard World convention where Mackie offered up his synopsis for Captain America 3.
Mackie said that Falcon and Captain America go after Bucky, and when they find him, they get rid of all the craziness out of Buck's head. All three then form a three-man duo and sing "he’s got a shield, he’s got an arm, and he’s got wings" and save the world.
Captain America, Falcon and Bucky beat up Batman and Superman.
Captain America 3 at one time shared the same release date as Batman Vs. Superman, on May 6, 2016, before WB moved the release date up.
Check out the 23:36 mark for more: