Given the question: Generate a question about the following movie plot: The year is 1863. The Civil War still rages. Far off in the Arizona desert, vanquished Confederate soldiers are being held at Fort Bravo by their Union captors. Surrounding them all is the monumental, inhospitable terrain and the implacably hostile Mescalero Apaches.Captain Roper (William Holden) of the US Army drags an escaped Confederate prisoner named Bailey back to the fort behind his horse. As they enter the grounds, the prisoners in the stockade resentfully glare at Roper. Roper tells his commanding officer that the man had ridden his horse until it gave out, then fled on foot before being ridden down. Roper soon finds that his brutal tactics are also unpopular with his commanding officer, his second-in-command Lieutenant Beecher (Richard Anderson), and the post doctor. The post commander pointedly reminds Roper that the prisoners nearly outnumber the garrison. Roper admits that his actions are designed to intimidate the restless prisoners and keep them in check.Confederate Captain Marsh (John Forsythe) asks Roper for permission to see the captured prisoner, which Roper grants. The young man is in a bad way, exhausted and dehydrated. He apologizes for his foolhardy escape attempt. Some of the more aggressive prisoners question Marsh's reluctance to order a mass escape.Roper leads a mounted patrol into the desert to escort an overdue supply convoy carrying rifles to the fort. They find the wagons overturned and burned, the drivers tortured to death on ant mounds. As the slain men are being laid to rest, Roper notices smoke and mirror signals in the distance. An attack is imminent. Beecher takes an arrow to the shoulder as the surprise attack commences. The Mescaleros wheel around the surrounded troopers, inflicting and incurring several casualties. The Apaches soon retreat into the distance.As night falls, the soldiers make camp and almost immediately hear gunfire. The same band of Apaches is pursuing a stagecoach through the desert, with both the shotgun guard and passengers returning fire. Roper's men...
The answer is:
Who plays Captain John Marsh?