Lynden Hoover is on the brink of a new beginning with a fast-growing tech company, but he first needs to confront the traumas of his past. At age eleven Lynden found a surrogate father in the form of a hobo riding a train, the Tramp, who abused and discarded Lynden. The memory of the Tramp has haunted Lynden's life, ruining his relationships. Now Lynden makes a snap decision, leaping into an open boxcar to find the Tramp and somehow punish him. There Lynden meets The Duke, a hobo who calls America's landscape his home. He's "Profesh" and clings to an honor code quickly fading into the past. The Duke has his own secrets, fleeing from the merciless Short Arm, a one-time friend who now wants The Duke dead. The Duke reluctantly agrees to teach Lynden how to be a Professional hobo, all while trying to stay ahead of the relentless Short Arm.

As Lynden and The Duke travel the rails a unique friendship forms, more than just that of mentor and apprentice. A special bond is formed as secrets are exposed, sacrifices made, and trusts are betrayed. Three determined people hurtle toward a spellbinding climax where pasts and futures collide, and lives hang in the balance.