The teams receive a clue telling them to travel from their Pit Stop in Potter's Field Park, England to Kingston, Jamaica and then take a taxi 90 miles to the Frenchman's Cove in Port Antonio. The Roadblock in this leg requires the teams to dance the limbo. Then, after spending the night at that location, they face a Detour that requires them to choose between Raft It or Build It. All teams choose the Build It option, which requires them to build a raft and then sail it a short distance across a river. The teams then travel 80 miles to a coconut and spice plantation in Montego Bay, the Pit Stop for the leg. In the final leg of the race, the teams first face an onion-cutting task and then a Detour in which all teams choose Tee rather than Pony, requiring them to hit a golf ball within a particular area. The teams later travel to San Juan, Puerto Rico and do a Roadblock that requires one team member to take a big dive off a bridge.

Rory is surprised by the performance review she receives from Logan's father, Mitchum Huntzberger, at the newspaper. Luke's plan to buy the Twickham house is threatened when Kirk makes a competing bid. Lorelai is thrilled when the travel magazine featuring The Dragonfly Inn hits the stands, but worries about Emily's reaction to the article. Meanwhile, Sookie goes into labor and Emily becomes a personal patron for a ballet dancer.

House apparently triggers a stroke in a clinic patient, but the major topic of discussion is House's imminent date with Cameron, The team must deal with the patient's odd lifestyle, overbearing "friend," and reluctant parents in order to stop the strokes and try to save his life. Meanwhile, Wilson, Cuddy and the team offer House and Cameron advice while laying odds on the outcome.

When Tony opens a mysterious letter thinking it's for him, a small puff of white powder comes out, releasing a possible deadly virus. Kate calls for help and as a precaution, she and Tony are isolated in a bio-hazard isolation room. While McGee and Gibbs are determined to discover who sent the envelope and how to cure their friends before its too late for them, Tony's health gets worse.

The Final 4 finalists will perform LIVE for the nation, vying for the American Idol crown. The contestants will sing their hearts out in hopes of winning America's vote and surviving another week in the competition.

Tonights themes: Country Music & Kenny Gamble and Leon Huff songs.

Performing tonight: Anthony Fedorov, Harold "Bo" Bice, Carrie Underwood, and Vonzell Solomon.

With their residencies over, there are big changes at Sacred Heart.

J.D. moves out to live on his own, while Turk and Carla consider a family change, creating another rift in their long friendship.

Jordan is hired to handle some paperwork for Dr. Kelso, which annoys Dr. Cox.

Elliot has a job interview at a different hospital thanks to her boyfriend Jake.

Cheryl and Dana think they have cause to worry when Dana's fianc - wants to race fast cars and Jim wants to take up skydiving.

Immediately following the 100th episode, a special half-hour retrospective episode takes a hilarious look at Cheryl and Jim's botched anniversary moments from years past.

Lying in a coma after his race car accident, Nathan dreams of what life would have been like if Dan had stayed with Karen and Lucas instead of marrying Deb. In this imaginary world, Lucas would have had the wealth and stature and Nathan would have been the one growing up on the wrong side of the tracks. After waking up, Nathan phones Haley and tells her he doesn't want her to come home.

In some hair twisting turn of events Veronica must betray someone she cares deeply about in order to solve the season-long mystery of who murdered her best friend Lilly Kane. But once she figures out who it is getting the person to confess or the police to believe her will put more people the just Veronica in danger.

Meanwhile, on the eve of a reception for the Governor of Calif., Jake Kane asks Duncan if he really wants to know what happened on the night Lilly died. Later, Keith awaits the results of a paternity test.

After a near-death experience in a jean boutique, Grace decides to write her will and enlists Will's legal expertise. To make sure she's fair when bequeathing her money, Grace visits Will's mother to find out how much Will plans to leave her and is shocked by what she finds. Thanks to Grace, Will also takes a look at his life and decides it's time to make a life altering career move. Meanwhile, Jack and Karen find an imposter teaching Jack's McFarland Method of acting.

For Opilio crab season 171 boats come out of Dutch Harbor, Alaska to hunt for crab. Some boats will sail as far as 450 miles to find Alaskan Gold. This season will be plagued with bad weather, repairs and death. One captain is forced to turn back for repairs, which is costing him money. An emergency signal rings for a sister boat and the radios are blaring with gale warnings. Ice is a deadly problem at sea ice build up can capsize a boat. At noon the Opilio crab season begins!

After a young woman's baby is tossed out of a car, Benson and Stabler investigate to find out what happened, and after learning the young woman is addicted to prescription pain killers, their investigation leads them to an elderly woman named Jenny Rogers, who lives with her son Kevin and daughter-in-law Carol. The young woman finally identifies Carol Rogers as the person who solds her the drugs, but when detectives go to confront Carol they find her body, and are left trying to uncover who really killed Carol. Stabler uses his influence as a police officer when his daughter, Kathleen, is arrested for drunk driving.

TONIGHT: Star of "Monster-in-Law," Wanda Sykes! Samantha Bee reports on "Heavy Betting." Plus, Jon investigates the use of web logs on television in "Blogisphere."