Mary was never the hot girl in school, nor the most outgoing or athletic. Mary is friendly and cute. She's a good girl, raised by a very religious mother who has sheltered her from the outside world.
Mary landed herself a hunky boyfriend, though, who cared more about how sweet she is than how big her boobs are. But Trevor is a horny teenager, and he wants to explore his sexuality with his girlfriend. Mary thinks sex is very scary, though. She can't imagine a boy putting his thing in her. She's so tiny!
When Trevor's sexy and confident older sister, Stacy, shows up for summer vacation, Mary learns a whole lot more about her sexuality than she ever thought she would.