While staying with friends in a mountain hotel, Keith Gridley finds out that he has no friends to play with--until he meets a tiny, talkative mouse named Ralph who has a fondness for Keith's two-wheel motorcycle. The boy and mouse soon become friends; and Ralph finds immense fun zipping around the hotel on Keith's motorcycle. But Keith is taken with a bad fever and Ralph, who overcomes his fears of many dangers, sets out to find the medicine which will help save his human friend. While staying with friends in a mountain hotel, Keith Gridley finds out that he has no friends to play with--until he meets a tiny, talkative mouse named Ralph who has a fondness for Keith's two-wheel motorcycle. The boy and mouse soon become friends; and Ralph finds immense fun zipping around the hotel on Keith's motorcycle. But Keith is taken with a bad fever and Ralph, who overcomes his fears of many dangers, sets out to find the medicine which will help save his human friend.