"Thunderbelt" is an episode of Special Agent Oso.
Professor Buffo trains Oso to open a vault where his inventions are stored. Oso needs to turn the dial and pull the handle to open it, but he fails to turn the dial all the way and he gets a special alert after setting off the alarm and getting himself trapped. A girl named Maya and her mom are going on a picnic in the car. Maya wants to show her mom how she can buckle her seat belt by herself, but she has trouble getting buckled up. So Oso teaches Maya how to buckle up before she and her mom drive to the picnic.
- The episode's title is a reference to the James Bond film Thunderball.