Lemon, a reclusive young woman with an unspecified chronic illness, sits in her apartment reading books about Nazism and reliving her life story. But as she tells the audience, that life story consists mostly of stories she herself was told in childhood by "Aunt Dan", a family friend. In flashback we see the miserable marriage of Lemon's parents and the child's eagerness for escape through Dan's stories.
Dan is a charismatic, eccentric figure, who tells the girl of her love affairs with women but also of an intense imaginary romance with Henry Kissinger. Dan's worldview is an application of Kissinger's doctrine of realpolitik to private life—amoral, ruthless, and seeing all relationships in terms of dominance and submission. As the play continues, Dan's stories become more bizarre, including one in which she conspires with a gangster's moll to murder a policeman. Lemon's inarticulate mother tries to stand up for the value of compassion, but she fails and is made to look foolish and weak by Dan's eloquence.
Dan is transformed, however, when she becomes ill some years later. Tended lovingly by a nurse, she comes to feel for the first time a sense of loving connection with the world. Lemon is bewildered and alienated by this change in her mentor, and Dan dies soon afterward.
Now an invalid herself, Lemon gains no similar insight from her illness or from her memories. Continuing her study of Nazism, she decides that compassion is simply a lie people tell to comfort themselves, and that this lie is only possible because the powerful of the world have taken on the burden of necessary violence. She concludes with the thought that ordinary people owe killers like Hitler and Kissinger a debt of gratitude for making their self-deceit possible.
