One of the most prominent themes in Science Fictoin, is the use of time manipulation. The rule is generally that time is immutable. in other words, you can't go back and mess with it. In this one, a young doctor and his friend are at a Civil War re-enactment at the Gettysburg battlefield. One is going to play a Union medic and the other a Confederate soldier. The latter has lived a life of desperation, unhappy with his lot. He is a bigot and believes that if the South had won the war, things would be better. Enter, a photographer with a Matthew Brady camera. He poses the two men and when the camera clicks, they are thrust into the battlefield in real time. They are picked up by Lee's forces and are kept prisoner. A series of rather unbelievable events occur where they try to manipulate their situations. A Captain who is going crazy from meningitis symptoms is in command and nothing they say can change things. The young medic is made to change sides in order to treat the troops, which he does so willingly. They are trying to get back, enlisting the help of the photographer, but the young zealot sees this as his chance to change things "for the better" in his eyes. This is an uneven, strange episode, with lots of weird implications. The wrap up is a bit confusing.