In 1850, a British garrison defends Fort Kandahar on the North West Frontier of British India. Lieutenant Case is a mixed race British officer under the command of Colonel Drewe. Case is despised by his colonel and a few jealous fellow officers for being part-native. However, due to his background, Case is useful to the British who use him to infiltrate the local tribes. The tribes, united under a war chieftain named Ali Khan, have been fomenting revolt against the British colonial forces. Disguised as a native, Lieutenant Case collects valuable intelligence for his regiment. Unfortunately, during a spying mission, Case and a fellow officer, Captain Connelly are discovered. Case escapes under the cover of darkness but Connelly is captured. On his return to Fort Kandahar, Case is accused of deliberately abandoning Connelly to the enemy and of cowardice as he made no attempt to rescue Connelly. The love affair between Connelly's wife and Case is well-known at the fort and many officers ...