Another Edd invention gone horribly wrong ends with Ed being rocketed through the air, powered by ultra-fizzy soda. Double-Dee and Eddy chase after him, when they come across a key on the ground. They speculate about what it might open, and Edd insists that they return it to its rightful owner. Eddy’s not listening, and tries to open every lock in the cul-de-sac with it. Nothing works, and Double-Dee finally manages to convince him to returning the key, but Eddy gets a better idea and holds it for ransom. None of the cul-de-sac kids own the key, but the Kankers show up and decide to take it anyway. They chase the Eds through the cul-de-sac, where they wind up at Ed’s house, and Ed realizes it was just the key to his back door, which fell out of a hole in his pocket.