The Unit is a covert team of U.S. Special Forces operatives who must undertake missions around the world. The latest newcomer is Bob Brown who joins Jonas' team and they set out to rescue an airliner filled with European businessmen who have been hijacked by terrorists. Meanwhile, Bob's wife Kim is struggling with how much control the Unit has on her own personal life.

The Unit is sent to Los Angeles to protect Mexico's drug minister who has been threatened with assassination and soon his wife and sons are kidnapped. At the base, a former Unit wife makes a return appearance in the hopes of luring the Unit members away. Tiffy is upset when Ryan orders Mack to take time off.

The team is sent to Pakistan to help an undercover operative foil a terrorist attack on many cities.

On the home front, Molly and Tiffy help one of Tiffy's former students and Kim and Bob welcome a new addition to their family.