It looks like young Keith Gridley will have a lonely summer, until he meets a talking mouse named Ralph. Ralph takes an immediate liking to Keith's toy motorcycle and can ride it just by making a motor noise. Ralph even acts heroically when Keith comes down with a nasty fever, while dodging cats, owls and a guest's noisy dog.

Join Ralph on a string of adventures after he runs away from home at the Mountain View Inn, and makes a new friend.

Ralph the mouse lives at the Mountain View Inn and loves his motorcycle. When the inn becomes overriden with mice and Ralph's friend Matt the bellboy must leave, Ralph asks his other friend Ryan to take him to school as part of a plan to help Matt.