Hey Duggee Season 10 Episode 9 The Key Badge

Roly is digging in the garden when his spade suddenly hits something. It's a key. But what does it do? Duggee has his key badge, they can find out through trial and error. The squirrels go on an adventure to work out what the key opens and what could be inside. But what is Trial and Error? Duggee explains that sometimes things work and sometimes they don't.