In this riveting drama series' fourth season, the dangerous missions continue for Sgt. Maj. Jonas Blane (Dennis Haysbert), Sgt. Bob Brown (Scott Foley), Sgt. Mack Gerhardt (Max Martini) and the rest of the men of the covert Special Forces crew. Commanded by Col. Tom Ryan (Robert Patrick), the team known as the Unit carries out hush-hush military operations that keep their devoted wives on tenterhooks back home.