Eric asks Matt to take his friend's daughter to the senior prom, but he is unaware of her tainted style and her being a harlot. Eric gets ""Snappy the Stegosaurus"" tickets from his ex-girlfriend for Ruthie. Meanwhile, Simon is uncomfortable after viewing a school film on the 'facts of life' while Ruthie learns the truth about her costume character hero. Also, Mary and Lucy trick their way into a date with boys they don't know, but the joke's on them.