Pulled by a thread through a fog, Mowzl arrives in the human world from a future time. In his home world Mowzl is a real mouse; here in the human world he is a toy - but alive, with a heart and feelings. He is found by Pip and LuLu, who are grown-ups, and LuLu makes him a woolen pouch in which he can fly. He talks with wild creatures and is upset to learn that the world is being badly damaged by what humans are doing. In his home world there are no humans to be seen and the world, or "wild web," is healthy.
Mowzl needs Pip to write his story to help him remember where he came from and how to get back, and Pip writes everything that happens. When Mowzl meets two children called Billy and Larky, they find that they can understand the wild talk too, but only when they are with the mouse, because of his magic. They are excited to learn from creatures about the wild web, and they want to do something to help. Billy and Larky soon get their friends involved, and they all listen to the stories that Mowzl tells. Gradually, the mystery of what happened to Mowzl before the fog is revealed.
The Adventures of Horatio Mowlz is an illustrated children's story that reflects on the impacts human activity is having on the environment, whilst taking readers on an adventure they will not forget.