第 4 季 共 22 集
播出时间：2008年9月29日
第 1 集 Sacrifice
播出时间：2008年9月29日
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.
第 2 集 Sudden Flight
播出时间：2008年10月6日
The team follows a scientist who may have been targeted by terrorists, hoping to link those same terrorists to a presidential assassination plot.
第 3 集 Sex Trade
播出时间：2008年10月13日
While the Unit is investigating a man they believe to be smuggling nuclear weapons, they discover that he is also smuggling women.
第 4 集 The Conduit
播出时间：2008年10月20日
Bob and Mac both find themselves in trouble when they each take assignments undercover. Bob as a chemist who hides cocaine by converting it to paint and Mac as a fighter trying to bust an illegal betting ring.
第 5 集 Dancing Lessons
播出时间：2008年10月27日
A nuclear scientist insists on making a deal with the team before revealing information about an imminent terrorist attack on a major U.S. city; Kim, Molly and Tiffy are asked to work under cover with Jonas.
第 6 集 Inquisition
播出时间：2008年11月3日
Hoping to con a terrorist into exposing his accomplices before they escape, the team produces phony evidence of an attack.
第 7 集 Into Hell (1)
播出时间：2008年11月10日
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.
第 8 集 Into Hell (2)
播出时间：2008年11月17日
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.
第 9 集 Shadow Riders
播出时间：2008年11月24日
Jonas and the team must travel through enemy territory to bring a young bride to her groom, preserving a truce between two warring Afghanistan tribes; Kim and Bob try to expose a man who is linked to terrorists.
第 10 集 Misled & Misguided
播出时间：2008年12月1日
The team's attempts to raid an anthrax lab are thwarted by an official from the Department of Defense (Michael McKean), who believes his high-tech intelligence is superior to field logic.
第 11 集 Switchblade
播出时间：1970年1月2日
Jonas and the team force a Department of Defense official to go with them on an assignment and experience the realities of war; A mysterious women shows up at Aerodyne headquarters. Kim is finally reunited with her kids.
第 12 集 Bad Beat
播出时间：2009年1月5日
Jonas plays a game of high stakes baccarat to win back the services of a CIA spy who has gone over to the other side. His success is also key in getting court martial charges against team member Bridget Sullivan dismissed.
第 13 集 The Spear of Destiny
播出时间：2009年1月12日
Jonas and a seriously wounded Mack take refuge in a monastery where he is ordered to steal the monks' most prized possession. Back home, Bob is asked to perform a dangerous mission that will reveal the darkest side of his job to Kim.
第 14 集 The Last Nazi
播出时间：2009年2月16日
The President orders the unit to capture a Nazi war criminal from his hiding place and deliver him to The Hague. In Washington, Tom Ryan confronts his past when he is offered a promotion to General
第 15 集 Hero
播出时间：2009年3月9日
The unit initiates a new team member while Jonas coaches his daughter Betsy, on how to respond to media questions about her kidnapping and rescue without blowing the cover story.
第 16 集 Hill 60
播出时间：2009年3月16日
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.
第 17 集 Flesh and Blood
播出时间：2009年3月23日
As the Unit fights to rescue Jonas's old friend, a broken helicopter gas tank and nearby guerillas impede their mission. Meanwhile, Tom goes to extreme measures to extract information from a recovering alcoholic whose husband may have been behind a terrorist attack.
第 18 集 Best Laid Plans
播出时间：2009年3月30日
The mission's plans go awry and Bob must run interference when Jonas and Mack are undercover to find the terrorists who killed the Vice President.
第 19 集 Whiplash
播出时间：2009年4月13日
When Sam attacks Bridget, the other members of the Unit must hunt him down.
第 20 集 Chaos Theory
播出时间：2009年4月27日
A random incident throws Jonas and Bob's carefully planned mission into chaos.
第 21 集 Endgame
播出时间：2009年5月4日
Molly is kidnapped and used as bait, while Jonas is out of the country looking into a Russian terrorist cell.
第 22 集 Unknown Soldier
播出时间：2009年5月11日
When several dirty bombs are found on American soil, The Unit is deployed to find and diffuse.<br />
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On the home front, the wives prepare for a wedding and a possible divorce.
