Some strange things get stolen – for example, the apples from your tree, bulbs from the garden or milk from your doorstep. You set a trap for the thief – and are very surprised when you find out who it is. Can you come to some sort of arrangement to stop this continuing?
What about when the blue tits first started pecking at the milk bottle tops? Or how to outwit the canniest of squirrels who help themselves to what’s on the bird feeder? Or what about a bit of memoir about the time the lads went scrumping and got into trouble?
Could you write something about the thieving magpie? Maybe a poem for a child? What about a story in rhyming couplets, again for children, about a petty thief who gets their comeuppance?
Perhaps a three-hander? The theft causes a rift between the two people who are affected? Catching the thief brings them back together. Or perhaps a two-hander when the thief and the one who has been robbed confront each other? Could you use a bigger cast, something along the lines of An Inspector Calls?
What’s the first thing that happens? Who notices the theft? What do you know about them? How does the situation escalate? Which clues does your protagonist get? Do they finally confront the thief? What happens? How has your protagonist changed as a result of what has happened?