The novel follows Elizabeth Egan, a serious woman living in a small Irish town who takes care of her sister and nephew after being abandoned by her mother. Her nephew Luke claims to have an imaginary friend named Ivan that only he can see. Though at first exasperated, Elizabeth plays along with Luke and finds that Ivan's presence helps bring her joy. A friendship and then romance blossoms between Elizabeth and Ivan, though he is invisible to everyone except Luke. However, Ivan's boss warns him that the time will come when Elizabeth can no longer see him, as he is an imaginary friend who can only be seen by those truly lonely. Reluctantly, Ivan realizes this time has come and says goodbye to Elizabeth, leaving her