A mysterious stranger, peanut butter biscuits, and a network of tunnels. What could this all mean? Sebastian, the guinea pig, finds these and more curious things when he leaves his home in Guinea Town to live in Aspen Meadow. He goes to meet his new neighbors, but can only find one inquisitive mouse named Hazel. She tells him that the local mice have been forced to go into hiding from a group of intimidating animals from the thickets.Sebastian believes that he can help them with his steady arm and handy rope, but will it be enough? If he fails, nobody will be brave enough to face the bullies. Unless… a courageous guinea pig, an optimistic mouse, and a clueless mayor can team up together.