In this film by director Francis Ford Coppola, Robin Williams stars as Jack, a boy who is growing normally, but at many times the normal rate. In a bizarre flashback, we see that he was born when his mother was only ten weeks pregnant. Kept out of school for years, the neighborhood children consider him a freak, and generally avoid him.
He is finally required to go to public school, and we catch up to him as he enters the fourth grade for the first time, a 10-year-old boy who appears to be a fully grown man in his 40s. His classmates tease him mercilessly until they begin to see the advantages of having him around.
He must also have some grown-up feelings to go along with his grown-up body, because he asks his teacher out for a date. When she refuses him, he goes off into town and gets into adult-type trouble as he courts nightclub denizen Dolores Durante (Fran Drescher) over the objections of her boyfriend.
Teacher Lawrence Woodruff (Bill Cosby) tries (with some success) to help Jack cope with his situation.