The Fighting Doctor (The Medicine Wagon Book #1)
Henry Wallace is the son of a prominent physician in late 1800s Boston; it's the last quarter of college before graduation. But Henry never graduates. Forced into a fight for his life, he kills a man who turns out to be the son of Boston's most notorious gangster.
Arrested by the police, who are paid off by the gangster, Henry is sentenced to prison for life. He makes a daring escape and becomes a fugitive - not only from the law, but he is constantly pursued by the gangster's hit men. Henry makes it to Denver where he meets the strange new owner of an unusual medicine wagon who changes his life in ways he never anticipated.