Heartland introduces us to Dr. Nathaniel Grant (Treat Williams) an intense and overworked lung and heart transplant surgeon at St. Jude Regional Transplant Center in Pittsburgh. Grant is forced to deal with working in the same hospital with his ex-wife Kate (Kari Matchett), who is the organ recovery coordinator. The two must put aside their past differences and battle the clock in order to save lives. (thetvdb.com)