1. The Scarecrow isn't very good at scaring away mice, he wants a music box to give as a gift to the farmer but has no money to buy one so he takes the mice he attracts to the pet shop to sell them so he can earn himself enough money to buy the music box and give it to the farmer.
2. Scarecrow owns a pet shop, a child with a music box enters the pet shop but then accidentally leaves the music box behind, scarecrow needs to bring it back to them.
3. Scarecrow is part of a pet shop display, comes alive at night and walks around petting the animals, finds a music box on the floor and not knowing what it is plays it, is really happy when he discovers what it does and wants to keep it. The next day a kid comes in looking for the music box but the scarecrow doesn't want to part with it, he ultimately chooses to leave it somewhere the owner will see in the morning so they can return it to the child.
I like these three, I'm just not sure which one is the best to go with, I think possibly the third one?