Marcus, a fellow bus passenger, is a man who has been neglected more by society than his family. As a young black ex-con, he is not the epitome of the person most would pick as a chaperone for their child's cross country trip. Yet rather than be held apart by their differences, Marcus and Sebastien are drawn together by the things that make us all alike.
Along the way, he acts as both guide and protector, as Virgil was to Dante and Jim to Huck Finn. Imparting his own style of wisdom, he shows Sebastien that, despite the darker parts of the human condition, people can and do care for one another. This is a modern day journey not just from one house to another. This is a journey taken by a young boy into manhood, and by the reader into his world. Like every trip, there are many stops along the way. But this journey differs in the way young Sebastien arrives at his destination. Greyhound is the story of this journey.