Cary was wounded at the battle of Mount Mora in 1916. He returned to England on leave and proposed marriage to Gertrude Ogilvie, the sister of a friend, whom he had been courting for years. Three months later, Cary returned to service as a colonial officer, leaving a pregnant Gertrude in England. Cary held several posts in Nigeria including that of magistrate and executive officer in Borgu. He began his African service as a stereotypical district officer, determined to bring order to the natives, but by the end of his service, he had come to see the Nigerians as individuals with hard lives.