Things have never looked quite so grim for George and Harold. The last time we saw our prank playing heroes, they had been transformed into evil zombie nerds. You might be wondering why their fearless leader, Captain Underpants, did not swoop in to save them from this terrible fate. The answer lies in the past. The villainous Tippy Tinkletrousers and his time traveling hijinks have completely changed history. Because of his interference, George and Harold never even created Captain Underpants in the first place. Now, the boys are stuck in a timeline where their superhero does not exist to protect them. Can the boys figure out a way to reverse time, fix the timeline, and get their superhero back? Prepare for a hilarious, action packed adventure filled with robotic boxers, time travel twists, and the ultimate fight for the future of silly comic books.