Dr. Gaudet, a respected brain surgeon, is falsely sentenced to ten years in prison on Devil's Island after treating a wounded political revolutionary. Upon his arrival, he faces the wrath of the cruel commandant, Col. Lucien. Dr. Gaudet leads an unsuccessful revolt against the inhumane conditions and as punishment, he and his comrades are sentenced to death. After the commandant's daughter suffers a head injury in a runaway accident, the commandant's wife forces him to ask Dr. Gaudet to save their daughter's life. Dr. Gaudet agrees, on the condition that they will not be executed. However, despite the successful operation, the commandant breaks his promise.
Madame Lucien arranges for Dr. Gaudet and his comrades to escape, but they are caught again. Sentenced to death once more, Dr. Gaudet is saved by Madame Lucien, who convinces the governor to stop the execution. Col. Lucien is also arrested for corruption. Dr. Gaudet is freed and a new regime promises reforms on the island.