The epistolary story is presented as the diary of disgraced surgeon Richard Pine, who, while attempting to smuggle a large amount of heroin on a cruise ship, finds himself marooned on a tiny island in the Pacific with very limited supplies and no food. A self-proclaimed "survivor" type, his diary entries documenting his day to day activities become more and more disjointed and raving, revealing his slow mental decay and eventual insanity caused by starvation, isolation, and drug use. Determined to hold out for rescue, he goes to horrifying lengths to survive.
After breaking his ankle while attempting to hunt a bird down, he amputates his foot, then realizes he has to eat it to survive. He continues to amputate his own limbs to use as a food source, ingesting the heroin for anesthesia during the operations. His last few diary entries, barely comprehensible, indicate he has cut off and eaten everything below his waist, as well as his ears, and drools uncontrollably as he ponders which body part to consume next. The diary entries end when he cuts off his left hand to eat.