Nolan is unexpectedly freed from Votanis Collective custody, at which point Amanda, Irisa and Berlin rush to save him from Kindzi's clutches. Elsewhere, Datak regrets seeking Doc Ywell's help against the Omec; and something startling is witnessed in the mines.
Riley is asked to the semi-formal dance by a classmate named Charlie and is torn whether to go with him or Lucas. Meanwhile, Cory’s brother Eric is paid a visit from an old friend, Jack Hunter.
After a high school lab experiment goes horribly wrong, and accidentally creating a "timenado" the universe is on the verge of being destroyed and it’s up to the slackers Mordecai and Rigby to go back in time and make the things right. Their mission: save their friendship and save the universe from themselves, or they will be fired.