A young man named Rupert Ullershaw falls in a love with the wife of his much older cousin, Lord Devene. The woman commits suicide, and the young Rupert promises his mother to henceforward "follow The Way of the Spirit, not that of the Flesh". After 11 years of soldiering in India and Egypt, Rupert returns home to England, where he marries his cousin Edith, a woman who is repelled by him but agrees to matrimony only because of Rupert's career prospects. Edith is actually in love with another of her cousins, the dastardly Dick, who arranges for Rupert to be sent back to Egypt, for a highly dangerous mission...