Have you ever wondered what it would be like to be the strongest boy in the world? Or the fastest? Or even the noisiest? Two ordinary young boys are about to find out! When the castle walls of Max and Finlay's den start crumbling away, little do the best mates know that everything is about to change . . . Trapped inside the wall is the ancient god Hercules and he needs the boys' help! The friends must complete a terrifying challenge every day for seven days and can choose only one of Hercules' amazing superpowers at a time to help them. In this second exciting Superpowers adventure, Max and Finlay have to deal with a vicious nine-headed river monster! Will they choose the right superpower?