The book begins by introducing, Katherine, a young teenager who begins a relationship with a boy in her school, Michael. However, she struggles to come to terms with the idea of engaging in a sexual relationship with him. As such, they begin their relationship on a slow and easy start, by going on dates.
Katherine’s friend, Erica, encourages her to lose her virginity as it is simply a physical act and means nothing more. As such, Katherine decides to have sex with Michael but her period starts. Instead, Michael teaches her how to perform oral sex and other sexual activities. After they have sex for the first time, he gifts Katherine a necklace saying "Forever...Michael". However, they are separated after summer and Katherine engages in a relationship with an older tennis instructor, Theo.
Things begin to get complicated, when Michael shows up to surprise Katherine and he sees her and Theo together. Eventually, she realizes that her relationship with Michael cannot last forever like they had initially hoped.
