In spring of 1858, Thompson Grey, a young farmer, travels to his father's estate seeking funds to expand his holdings. He covets the land. Far overstaying his visit, he returns home to find that his absence has contributed to a devastating family tragedy. Haunted by remorse, Thompson abandons his farm and begins a westward exile in the attempt to outpace his grief. During his wanderings, he encounters emigrants along the Santa Fe Trail who force him to assert his values, re-awaken his connection with humanity, and reevaluate his ties to the land. Unwittingly, he finds himself at journey's end in the one place where his strongest temptations are able to overtake him and once again put him to the test.

Set against the backdrop of the Great Plains during the years just preceding the Civil War, Crossing Purgatory deals with questions of unprincipled ambition, guilt, and the price one man is willing to pay for atonement.