Jonas and his team must track down surface-to-air missles before they are smuggled out of Brazil after a deal with a drug lord falls through. Jonas gets help from a local boy who informs the team where the SAMs have been taken to be shipped. Meanwhile back on the base, Kim ends up causing even more trouble when she insists that the “Family Readiness Group” deals with what she deems more serious issues. Also, Williams tries to find a way to tell the woman he wants to marry that he is actually a Unit member and not a clerk on the base like she believes.

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.

Jonas and the team carry out an assasination of a terrorist in Spain. However, they soon find out that the government called off the mission and will now not protect them in the country which means there only hope is to escape. Back at the base, Molly learns that her daughter Betsy wants to drop out of college and Kim thinks about taking a college course herself.

The crew must fly to Afghanistan to assassinate a high ranking member of the Taliban. However, one of their team helicopters ends up going down in enemy territory, placing the entire crew in jeopardy. Back at the base, Molly confronts a friend and retired Unit veteran about his addiction to painkillers and Kim ends up getting a job at the local radio station.

Jonas goes on a solo mission, enlisting the help of some local militants to hunt down a terrorist known as "The Butcher". Charles is still recovering in the hospital, Mack takes on the task of arranging Hector's final funeral preparations, with the help of the other wives and Bob has been ordered to deal with the rescued journalist. Ryan must deal with the man sent by Washington to oversee the cover story.

The Unit is in Lebanon when Charles is seriously wounded. They must think and act quickly to save his life. On the Home Front, Tiffy's problems continue to build when a man attempts to tow her car. The women stand up and fight to protect her.

Jonas attempts to rescue a group of American missionaries in hiding in Indonesia. However, he soon realizes the mission is going to take more manpower then he expected. At the base, Mac ends up being shot by Bob during a training exercise and Molly, Kim and Tiffy prepare to host a visiting senator.

The Unit is called in to help out the local SWAT team when a prominent school in Virginia is taken over by shooters. They must determine how to free the hostages without the students getting injured. On the homefront, Lissy has a young man interested in her, which turns into a delicate situation as he is the son of an Officer. Kim further complicates this matter, when she defies Tiffy’s orders and Lissy pays the price.

The team travels to Iraq to save Jonas' daughter, who has been kidnapped; Col. Ryan must face the consequences for his adultery with Mack's wife.

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 Unit faces its greatest threat when they are investigated by the Government for their actions. Each man must make difficult choices, which may put their entire team in jeopardy.

While women are being secretly relocated and moved off the base for their own safety, Jonas and the team must unravel an assassination plot against the vice president and president elect.

When several dirty bombs are found on American soil, The Unit is deployed to find and diffuse. On the home front, the wives prepare for a wedding and a possible divorce.

The Unit is sent to Pakistan to retrieve three suspected terrorists when they run into trouble with the local forces. They find a U.S. base with a small force of troops that do not respect their commanding officer. Jonas takes control of the combined group and prepares them for the impending attacks.

Jonas is still in hiding, Mack and Hector are still imprisoned, Charles is on the run, Bob is in Mexico, working for the CIA and Colonel Ryan is again called to answer question before a Congressional hearing.

Jonas works out a plan and the team reunites to clear their reputation. Kim is working behind the scenes to keep the CIA away from the other wives.

The team keeps trying to rescue Betsy Blane from Syrian captors; Mack has an opportunity to get revenge on Ryan for his affair with Tiffy.

Unable to communicate with the outside world, the Unit and their families must survive when a deadly gas poisons anyone in their community who steps outside.

Molly is kidnapped and used as bait, while Jonas is out of the country looking into a Russian terrorist cell.

While struggling to keep himself and his translator alive after their helicopter crashes in Siberia, Bob remembers the process in which he went through to become a member of the Unit.

A mission is put on hold in South America because the team has to rescue to two members trapped by snipers. Meanwhile, the wives take on a mission of their own to help a unit widow.

Jonas and Molly celebrate the overdue presentation of George Blane with the Silver Star for his service in Korea, but are interrupted by the discovery that their nephew is beating his wife. Jonas attempts to remedy his nephew's behavior by sharing memories of his father after he returned from war.Meanwhile, Mack offers help to a jet that needs assistance to land after the pilot dies in mid flight and the jet flies into a restricted area. Piloting the jet is a former Ranger, with an alcohol problem and Mack calls Bob into help him.

Jonas is assigned to protect an US Senator on a humanitarian mission to an Asian country. Although he has been secretly ordered by the President of the United States to meet with the former Prince who is planning a revolution against the current regime. On the home front, Molly, Kim and Tiffy work with Jeremy in planning a surprise for Crystal.

The team follows a scientist who may have been targeted by terrorists, hoping to link those same terrorists to a presidential assassination plot.

A random incident throws Jonas and Bob's carefully planned mission into chaos.