In Episode 4, we return to the Missouri History Museum for a detailed explanation about the Union Arsenal in St. Louis, and the events at Camp Jackson. Both Unionists and Confederates were positioning themselves to control the St. Louis Arsenal, which is the largest arsenal in the state. Secessionist-leaning Governor Claiborne Jackson called upon the militia to gather at Camp Jackson, currently the site of St. Louis University. Union General Nathaniel Lyon believes that act is outrageous, and sets out to capture Camp Jackson. That created level of tension which could only lead to violence.