Liza Winthrop, 17, first meets Annie Kenyon, also 17, at the Metropolitan Art Museum in New York, where she's gone to work on an assignment. Both Liza and Annie are avid museum browsers. Both love medieval lore and history and both have a flare for the dramatic. They are instantly drawn to each other, and their friendship grows quickly and deeply.

Liza attends an exclusive prep school, Annie a public high school in a working class area where she lives with her Italian immigrant family. Liza is student body president and a much respected leader. As the relationship deepens, both girls begin to realize with some trepidation that there's a dimension to it they didn't expect. Annie realizes before Liza that their attraction is sexual as well as spiritual. Liza finds she has some hard thinking and reading to do about homosexuality.

Their relationship becomes public in a traumatic way when, housesitting for two teachers at Liza's school (who, they discover, are lesbians, though the fact has never been made public) they are discovered by a punitive administrator who dismisses the two teachers and threatens Liza with expulsion. She is reinstated by the board of trustees, but emotional stress with peers and family remain to be worked out.

Ultimately, she finds she can let go of friendships that falter on this issue, and her family supports her, though her parents have to work through their own ambivalence. Annie goes to Berkeley, Liza to MIT, and after some months of silence, they resume contact with hope of reviving a relationship they still cherish, perhaps the more for the lessons it's brought with it.