Kathy has seemingly been happily married to Peter, but their relationship has grown routine. She cannot help but wonder what would happen if she ever got together with her high school sweetheart, Tom, who she had never slept with. Being married prevents her from acting on that, so she asks her friend, Emily, to look Tom up when she goes to Denver, and to sleep with him, then tell Kathy what it was like. Emily does this, but when she tells Kathy that Tom is awesome and they had sex all night, their friendship suffers, as does Kathy's marriage. Things become even more complicated when Emily learns she is pregnant, and is uncertain if Tom or her boyfriend, Elliot is the father.