Good night owl

Owl is ready for bed. But as soon as he settles in, he hears a strange noise. He'll never get to sleep unless he can figure out what's going on! He looks everywhere - in his cupboard, underneath the floorboards - even in his walls. But while he's busy tearing his house apart, he doesn't notice one tiny, squeaky, mouse-shaped detail... Will Owl ever get a good night's sleep?