1854. The Kansas-Nebraska Act becomes law. After a generation of containment by the Missouri Compromise, a path is created for slavery to expand. Southerners are ecstatic and northerners enraged. Both sides rush settlers to the Kansas Territory, seeking to gain the majority. Guerilla warfare results, with Americans killing Americans.

Monty Tolliver, a former congressman from Ohio, inspired by a remote figure from his past, moves to Kansas, determined to make it a free state. Two young men, Billy Rutledge from Mississippi and Robert Geddis from Rhode Island, seek a new start on life in Kansas. They all find in Kansas a land embroiled in violence, and cross paths with abolitionist John Brown, Abraham Lincoln, and other historical figures. When a grisly double murder occurs, the investigation uncovers secret societies, betrayals, and cover ups.

Chronicling the "Bleeding Kansas" era of the 1850s, a precursor to the Civil War, And Union No More confirms that one cannot fully understand the latter without knowledge of the former.