The NCIS team investigates a bizarre murder of a sergeant whose suspicious private life might be the reason why he got killed.

The auditions continue on American Idol as the judges continue their quest to find the next singing superstar from Jacksonville, FL.

It's Super Bowl week on the Biggest Loser ranch, and that means food, football and fun with two special guest stars - celebrity chef Curtis Stone and NFL MVP Kurt Warner. First, Stone tests the contestants' calorie knowledge of traditional Super Bowl snacks, then teaches them how to make healthier versions. Later, one contestant has to leave the ranch for a very important arrival at home, while another surprises her teammates with a new change in attitude. Then it's time for the challenge, when Warner puts the contestants through an NFL-style drill that will give the winner an especially valuable prize this week. Then the partners who were sent home for 30 days while their teammates stayed on the ranch are welcomed back. But the reunion celebration is quickly followed by a tense weigh-in and elimination that will leave one team heading home.

Featuring a special appearance from Sesame Workshop's "Muppets", J.D. learns a lesson about the gift of compassion, while Elliot gets scammed by intern Katie to secure a spot on Turk's team.

Orange-and-black wings fill the sky as NOVA charts one of nature's most remarkable phenomena: the epic migration of monarch butterflies across North America. To capture a butterfly's point of view, NOVA's filmmakers used a helicopter, ultralight, and hot-air balloon for aerial views along the transcontinental route. This wondrous annual migration, which scientists are just beginning to fathom, is an endangered phenomenon that could dwindle to insignificance if the giant firs that the butterflies cling to during the winter disappear.

Elliot and J.D. encounter a road block in their newfound romantic relationship, and Dr. Cox considers taking the now vacant Chief of Medicine post.

Mike visits California, where he harvests walnuts in Meridian and makes goose-down comforters and pillows in Tulelake.

Olivia, Walter and Peter are brought in to try and stop a killer with the ability to liquefy the human brain.

Sean tries to deal with his feelings for Julia, while Liz and Christian analyze their relationship and Christian meets someone who understands what he is experiencing with his breast cancer.

Elena is forced to face the consequences of her past, as the team is put on the case to search for her former partner who went missing during an undercover sting.

While helping a National Guardsman whose home was foreclosed by an unprincipled construction firm, Nate jeopardises both his team and their job after he seeks solacement in the bottle.

An exploration of mysterious phenomenon, including alcohol clouds in space, pulsar planets, the possibility of a planet beyond Neptune, and dark matter.

Editor of "Washington Week", Gwen Ifill

When Richard's mother is caught pilfering booze from the store, Leslie uses offbeat methods to help her conquer her alcohol problem. Meanwhile, he also plays Cupid for Richard, helping the clean-cut cashier get a date.

Tonight Stephen welcomes high-wire walker and subject of the documentary Man on Wire, Philippe Petit.

The on going feud between Tom and Earl Kelly escalates. Melissa holds a speed dating event.

Ian and Sophie Cooper attempt to create a property in Bath.