Twins Eddie and Izzie love animals. They want to look after ALL the school pets in the holidays - but the only one left is the grumpy lizard. The lizard cheers up once he goes home with them and eats food he likes - they name him after his favourite. Then Cornflake grows two bumps on his back, which gradually turn into wings - He's really a dragon! The twins know they have to keep such a rare animal secret, but it's hard in a small flat, especially when Cornflake starts breathing fire. When a man turns up asking awkward questions, they really start to worry. How can they keep Cornflake safe?