Eight-year old Ivy isn't allowed a pet, so she gets the shock of her life when a strange cat splash-lands in her bath. The shocks get bigger when Ivy discovers that the cat can talk and likes to be called Queen Sardine!

Queen Sardine tells Ivy that she needs help - there's a monster living in her home and she's scared to go back. Ivy loves cats, but helping Queen Sardine comes with its own problems. Not only does Ivy have to keep the cat a secret from her mum, she soon realises Queen Sardine is one demanding feline.