Owain and Tilly find out how a balloon can help keep a secret, fly a helicopter that you can build at home, explore why hot things sometimes freeze faster than cold, and discover the nature-inspired robots that could take over the world!

Owain and Tilly find out how to make super-cool spy tools, take one giant leap for mankind without leaving the ground, learn that warm keys are good for opening doors, and discover a surprising way to turn milk into plastic!