When Scissors constructs a lie that it was Rock's birthday in an opportunity to get free cake, the trio gets caught and is on the run from the Birthday Police, and hide in an underground cave with other people who have done the same thing.

Paper falls in love with his next door neighbor Pencil, and when he becomes desperate to impress her, he lies about being a proper inventor. Things spill over when he ends up being the Earth's only hope against an alien invasion led by hippos.