July, 1863. The small Pennsylvania town of Gettysburg is torn apart when two armies collide. Over the next three days, more than 50,000 men will become casualties, while the residents of Gettysburg take shelter in their cellars. On the southern edge of town, a brick house, owned by one Harvey Sweney, is taken over by Confederate skirmishers. From upstairs in the attic, snipers pour a withering hail of fire down on the Union position at Cemetery Hill...