When a fellow agent is murdered, the NCIS teams heads into the desert to locate a woman who might hold the answer to the mystery murder.

This week, the contestants hike up a hill to find over 100 keys, but only two teams will find the keys that unlock the Biggest Loser gym. The rest of the teams have to learn to creatively work out all week without the use of the gym. Later, a rowing machine challenge pits team against team, and then a surprising turn of events leads to one contestant heading home.

Steve Wilson makes Nathan an unexpected offer.

Once every 48 years, bamboo forests in parts of northeast India go into exuberant flower. Then, like clockwork, the flowering is invariably followed by a plague of black rats that appear to spring from nowhere to spread destruction and famine in their wake. For the first time on film, NOVA and National Geographic capture this rat population explosion in vivid detail and show how scientists are unraveling the connections between bamboo flowering and rat outbreaks. Ultimately, their research should help local people better cope with the next attack-due in 2056.

Highlights from past shows

In the first season finale, as Marco and Keith plan for their wedding, Rose and Sage's relationship takes a bad turn when Rose decides to ditch their annual plans for spring break and Sage becomes upset. Zachary too feels that Rose is changing rather quickly, and worries about the future of their relationship. Meanwhile, Megan and Lily discover that Arthur is drinking again and that Shelby wants him to give her another chance. Also, Will and Megan have a fight and break up.

Harry Houdini is in town. He is to perform in a local theater but before the performance he offers a glimpse of what he does at the precinct. He then offers tickets to his performance. While doing his tricks, the bank next to the theater is burglarized. Brackenreid who was suspicious of him from the beginning is certain Houdini did it. However, Murdoch is not and he tries to find who is the real culprit.

Christian decides to employ Dr. Logan Taper for the practice, while Sean is revisited by a former client from Miami to have plastic surgery so she can attract suitors once her husband dies.

Nate attempts to reform his fractured team after coming out of hiding to directly challenge Sterling and Blackpoole by stealing both David statuettes. However, the stakes are high and could result in the incarceration of his friends.

Actor Ricky Gervais

Leslie wants to commemorate the store's 150th anniversary by doing something special. He decides to salute the occasion by running the store as it was when it first opened, which goes horribly wrong. Elsewhere, Ingrid has herself a new boyfriend, but there may be more about him than meets the eye.

Tonight Stephen welcomes former Supreme Court clerk, Slate publisher and co-author of The Great Decision: Jefferson, Adams, Marshall, and the Battle for the Supreme Court, Cliff Sloan.

Rachel and Eddie are pleased by the report the school inspectors give the place. Earl, Maxine and Steph are dangered by a tragedy that happens.

Adi Nortje and Daren Howarth attempt to build a property in Brittany, France made from recycled materials.