Thea Galehouse has always known how to take care of herself. With a flighty club-owner mom and a standoffish, recovering-alcoholic dad, Thea has made her own way in her hometown of New York, attending the prestigious and competitive Stuyvesant High School. But one chat with Will, a handsome and witty senior, and she's a goner - completely hooked on him and unable to concentrate on anything else. Always worried that she loves Will more than he loves her, Thea is pleasantly surprised when their romance weathers his move to college and Will goes out of his way to involve her in his life. But then, Thea misses a period.