The team is left in shambles as Jonas continues to elude an assassin and Bob may be reporting to another agency. But in the midst of it all, Ryan tries everything to get the team back together.

Jonas works to uncover the conspiracy that tore his team apart. He must find a way to reunite the unit and clear Col. Tom Ryan's, all while keeping his wife, and the other men's wives, from harm or CIA scrutiny.

Now that the team is back together, they all head out to stop a plane with deadly nerve gas from reaching Ft. Griffith. Meanwhile, Kim has to broadcast a fake weather bulletin so that all personnel will take cover.

Bob, Williams and Mack head to Abidjan to rescue Embassy staff and their families. Meanwhile, Jonas' daughter decides to enlist, so Jonas tests her strength and dedication.

The team tries to recover a chip with information on it that could prevent a terrorist attack on the United States. Meanwhile, Kim is placed on bed rest and Bob struggles with taking care of the kids.

Jonas, Mack and Grey are assigned to keep a pop star safe while Bob and an escort from the Justice Department return a prisoner to his home country for execution.

Jonas and Williams must perform emergency surgery on Grey when he is injured during a mission. Later, the team has to cope with a devistating loss.

Jonas seeks to avenge the death of one of their own; Brown works with a journalist to make sure The Unit isn't betrayed by him; and the team comes together to cope with Williams' death.

Grey goes undercover to gather information on gang members who are stealing explosives that may possibly end up in the wrong hands.

Bob wrestles with a moral conflict during a sniper mission. Elsewhere, Tiffy and Kim discover some surprising information about Molly.

In London, Jonas teams up with a British MI5 agent who is suspected of collusion with a Russian scientist they are tracking. Jonas, 's assignment to discern his partner, 's loyalty is complicated by the fact that Jonas once had been engaged to the man, 's wife.