SpongeBob (Tom Kenny) loves his pet snail Gary, but one day he comes home one day to find Gary has been snail-napped. Distraught, SpongeBob doesn't know what to do until his friend Patrick (Bill Fagerbakke) offers to help him and the two embark on an epic adventure to The Lost City of Atlantic City to bring Gary home.

They head off in a car/boat driven by a robot named Otto (Awkwafina), on a perilous and hilarious rescue mission, including stops in an old western town filled with zombie cowboys, a meeting with a mystic Sage (Keanu Reeves) who is made out of sage, a trip to a carnival and a visit with King Poseidon. We even get a look at how SpongeBob met his friends years earlier at Camp Coral. Along the way SpongeBob and his pals prove there's nothing more important or stronger than the power of friendship.