The team investigates the shooting of a Marine and uncovers more to his life than anyone would have ever imagined.

The eight female semifinalists perform live for America and the American Idol judges. After the performances, it is once again up to America to vote. Tune in to see who sizzles and who fizzles. Performing Tonight Are: Crystal Bowersox Didi Benami Katelyn Epperly Katie Stevens Lacey Brown Lilly Scott Paige Miles Siobhan Magnus

Naomi returns from her vacation in St. Bart's excited to spend time with Liam, which leads to the two getting up close and personal in his newly built boat. Adrianna and Gia bond during an AA meeting and establish a support system for each other which leads to the two sharing a kiss at the Beach Club. Navid and Dixon devise a plan to eliminate Jasper from Annie's life, but never anticipate the outcome of a school drug search. Dixon attempts to rekindle his relationship with Silver, while Silver hides her true feelings for Teddy. Harry and Debbie run into Kelly while attending a school function and Debbie confronts Kelly about having a crush on Harry.

The teams pull trucks and load crates onto the vehicles for a challenge that ends with a puzzle. Later, the contestants work eight-hour shifts at the food bank and must learn to fit workout sessions into their schedules.

Ilana discovers the extent of Ben's involvement in Jacob's death, while Hurley and Jack meet Richard. In another life, Dr. Ben Linus, a high school history teacher, must make an important choice.

After a sailor is killed during an underground street race, the NCIS team determines that his car had been sabotaged and contained confidential Navy equipment.

Meanwhile, Callen is forced to take traffic school.

Violet asks Auggie to leave town with her. Amanda puts Ella in charge of a lavish party at her house for the arrival of her boyfriend Ben. Riley asks Jonah if they can start over. Amanda spies Ella and Ben together in a compromising position, she lashes out.

Inspector Breckenreid's son is kidnapped and the Murdoch team must race against time to save the boy.

Officers Cooper and Sherman are the first to arrive on the scene in Hancock Park where a mother has been beaten to death and her young daughters are assaulted and murdered in their bedrooms. Personality conflicts continue to build between Det. Adams and her new partner. Sherman confronts his partner about Cooper's increasing reliance on pain killers.

The Forgotten squad looks for the killer of an 8 year old girl (who died five years ago), and has to match their wits against a multiple child murderer who likes to leave clues in the form of puzzles.

As Peter strategizes on how to handle his retrial and the next steps in his public rehabilitation, Alicia and Will defend an attorney arrested for murder.

Adam and Kristina try to cope with their son's Asperger's Syndrome. Sarah is job hunting with the help of Zeek that pushes her to dream big. Meanwhile, Crosby bonds with his son and Julia deals with a difficult mom from Sydney's school.

Neal and Alex try to get their hands on the music box while Peter seeks for help to get finally rid of Fowler.

After finding out that Denise has been cheating on him, Craig teams up with Sammy to go on a drinking binge as part of BMS' Marathon Monday tradition. Alex falls for a girl in marching band, who happens to share his view of college life.

While planning a grand re-opening of Players, Ken's repeated attempts to prove to the staff that he's capable of having fun backfires.

Guest: Marc Thiessen is former White House speech writer for President Bush and talks about his new book Courting Disaster: How the CIA Kept America Safe and How Barack Obama Is Inviting the Next Attack.

Annie Leonard

Actress Julianna Margulies; grocery bagging champion Kyle Perry; Broken Bells perform.

Christoph Waltz; Animal Expert Dave Salmoni; musical performance by Joan Jett and The Blackhearts.