Kyle's not pleased about having to spend time with his eccentric old grandad, but his feelings change when his grandad introduces him to the marvels that can be found in the stream at the bottom of his garden.
Once filthy and full of rubbish, the beck has been cleaned up and is now full of amazing creatures. But this magical world is under threat from a new development.
Kyle's grandad is determined to stop the builders, but when he falls ill, Kyle decides to carry out the plan himself. Can he triumph over school bullies, security guards and a vicious guard dog to safeguard the future of the beck?