Susan Morrow receives a book manuscript from her ex-husband – a man she left 20 years earlier – asking for her opinion of his writing. As she reads, she is drawn into the fictional life of Tony Hastings, a mathematics professor whose family vacation turns violent.

Adapted from a 1964 novel of the same name, the film follows a day in the life of George Falconer, a British college professor reeling with the recent and sudden loss of his longtime partner. This traumatic event makes George challenge his own will to live as he seeks the console of close friend Charley who is struggling with her own questions about life.