Amy's unusual pet has won the family a summer vacation in the school Pet Parade but Mum and Dad say Rocky has to stay home because no pets are allowed at the beach cottages. How is that fair? They wouldn't be going to the seaside if weren't for Rocky. Amy has to find a way to take him. Luckily the strange neighbour who gave Rocky to Amy has an interesting solution to the 'no pets' problem. Mum and Dad don't know it but an extra guest has come along to join the summer fun. Can Rocky stay Amy's secret? Perhaps her holiday will be a monstrously more fun if he doesn't...