A Severe Mercy is Sheldon Vanauken's autobiographical account of the love he shared with his wife, the friendship he developed with C. S. Lewis, and his growth as a Christian.
Vanauken, called "Van" for short, relays that he and his wife Jean Davis, "Davy" for short, met as older teenagers, and their lengthy, intimate conversations soon turned to what it would be like to be married. Soon, they married secretly and spent a summer living on Van's family estate in England.
At the start of World War II, Van enlists and is sent to Hawaii, and Davy pursues him. After the war, they devote themselves to learning how to sail and spend some time sailing around the Florida Keys as Van publishes articles for a yachting magazine. Soon, they both begin an education at Yale University. Later, they head back to England to pursue degrees at Oxford.
It's at Oxford when they begin to meet intellectual Christian friends. One of the intellectual Christian thinkers is C. S. Lewis, who is head of the literature department at Cambridge. Not only do Van and Davy read all of his books, they also enter into a close friendship with C. S. Lewis through an exchange of letters. As they learn more and more about Christianity, they begin to reach spiritual understanding and develop a passion for the faith.
After Oxford, the couple returns to the States, where Van accepts a teaching position in English at Lynchburg College in Virginia. There, they begin a Christian study group, and Davy participates wholeheartedly. At this point, Van begins to suffer from some jealousy because he feels his role in her life is being replaced by God.
Sadly, soon, Davy is overcome by illness and passes away. As Van comes to grips with his grief, he begins to realize her death answered her prayer for his total acceptance of God. He realized that Davy was the one thing still separating him from God, and with her gone, he could now feel liberated to give himself wholly to God.