Hard-charging United States Marine Corps Major John D. “Mac” MacGillis is commander of the infantry training school. MacGillis's life is changed when he falls in love with a liberal journalist, Polly Cooper. The show follows Mac in his work life—where he deals with Lt. Eugene Holowachuk (Matt Mulhern), Sgt. Byron James (Marlon Archey) and Merilee Gunderson (Whitney Kershaw) – as well as his home life as he learns to live with Polly's three daughters, Elizabeth, Robin, and Casey.