Billy's feeling nervous about his first overnight stay in hospital, as he has to have his tonsils out. The Mini Monsters are determined to help him, and ask to come along too. But there's so much for them to explore in the hospital... will they get back to Billy in time for his operation? And will anyone find out what they've been up to? Another fun-to-read Billy and the Mini Monsters story, with a message of overcoming your fears.