When a controversial DJ and a Naval Officer are shot to death, the team uncovers a sinister plan.

As Halloween approaches in Tree Hill, Brooke and Julian get an unexpected visitor, and Nathan begins a new career. Meanwhile, Clay and Quinn struggle with life back at the beach house, and Haley and Mia host an open mic night at Tric.

Audrina Patridge and Tony, Kyle Massey and Lacey, Rick Fox and Cheryl, Brandy and Maks, Bristol Pailin and Mark, Kurt Warner and Anna, Florence Henderson and Corky, and Jennifer Grey and Derek are up to be eliminated and Special musical guests Shakira and Jason Derullio are performing. Who goes home and who stays?

Mel hears something in the attic but when she goes to investigate it is the last thing she expected.

While patrolling the park at night in an effort to catch a mugger, Jim is mistaken for a murderous vigilante who has begun targeting the robbers; Stephanie makes a discovery that could explain how she and her family got their powers; Daphne uses her telepathic abilities to get into an exclusive party reserved for only the cool high school kids; and JJ tries out for the football team - with a lot of help from his power.

Five contestants who didn't make it to the ranch in the premiere episode now return, all vying for a spot back in the competition. Whoever has the highest percentage of weight loss wins their way back in, and also wins one of the most important, game-changing decisions of the season when the competition moves to blue team vs. black team this week. In their first challenge as blue team vs. black, they race through food stations in downtown Los Angeles, answering food trivia questions that come with a physical challenge penalty if they choose the wrong answer. And the stakes are high with the winning team getting 'The Biggest Loser' meal plan by Ediets for each member, plus the always-coveted reward of letters from home. When one team proves victorious, members of the losing team get a heartwarming surprise. Later, the drama heats up when a rumor spreads of one team possibly throwing the weigh-in, and after a tense weigh-in, the players send another contestant home.

A wild night in Kings Cross teaches Nathan not to judge a book by its cover.

How did medieval builders reach such spectacular heights using only hand tools to create the great cathedrals? The filmmakers behind NOVA's award-winning documentary Secrets of the Parthenon take viewers on a dazzling new architectural journey, inside those majestic marvels and jewels of Gothic architecture. Carved from a 100 million pounds of stone and sometimes more than 100 years in the making, some now teeter on the brink of catastrophic collapse. To save them, an international team of engineers, architects, art historians, and computer scientists searches the naves, bays, and bell-towers for clues to how the dream of these temples of human achievement and artistry became a reality. NOVA teams perform hands-on experiments to learn the architectural secrets that the cathedral builders used to erect their towering, glass-filled walls and reveal the hidden formulas, drawn from the Bible, that drove medieval builders ever upward.

Mike visits a Texas ranch that breeds exotic animals like sloths, lemurs, camels, and bearcats.

Adam gets the chance to alter the regret that led him to a life of violence and crime. It's a path that Adam is sure he cannot change - that is, until he winds up in a surprising new present.

Callen's ex-partner, Tracy Keller, holds a Navy Recruitment Center hostage. Callen mediates with her to learn more about a hijacked shipment of missiles.

The crew of the Destiny faces more interplanetary peril. As it continues to grow, Chloe starts to go through some unexplained changes. Eli becomes concerned and the rest of the ship starts to follow his worries as they try to get to the bottom of Chloe's uncharacteristic confusion. Is it really Chloe or something else?

Cate and Ryan go on a staycation to a local hotel to help make up for the fact that they never had a proper honeymoon. Unfortunately for them, Baze's work retreat is at the same hotel.

Steve sets out to prove to Emmy he can be less extravagant by throwing an environmentally friendly soiree.

The Grim Bastards have a problem that could jeopardize Samcro's new business arrangements.

Alicia risks disbarment when Childs' office suspects her of an ethics violation, which could also ruin Peter's political campaign. Meanwhile, a third candidate is revealed in the campaign for state's attorney.

Zeek once again tries to go overboard with the Halloween celebration and is upset when Haddie, Amber and Drew refuse to join in the fun. Meanwhile, Adam and Kristina are nervous about Max's new plans for the holiday. Sarah's relationship with Gordon gets complicated after she confronts him about their kiss. Elsewhere, Julia struggles with her belief in women's rights when Sydney chooses a costume she doesn't approve of.

In New Cap City, a vengeful Tamara confronts fellow "deadwalker" Zoe.
Clarice and Amanda depart from the cabin, Amanda to an empty home and Clarice to a kidnapped Lacy.
Meanwhile, Daniel has successfully won back his company, but there's one more part of the process that Daniel isn't ready for.

When a teenage girl is killed at the same high school Lt. Mason's daughter, Simone, attends, a chill runs through the precinct. The suspects include a lecherous construction worker with a record and even the victim's boyfriend. Meanwhile, the 21-year-old son of a prominent defense attorney is murdered after hours in a Greek restaurant, and it looks to be an inside job.

When the Super Villain prison system mysteriously shuts down, chaos is unleashed on the world. Earth's Mightiest Heroes must now band together as the Avengers to protect the planet from the threats that no single Super Hero could face alone. Their first task is to try and stop Graviton, a being whose power dwarfs anything ever seen. He's after Nick Fury, but will destroy the world to get to him. Individually the heroes have no chance, but together they can make a difference.

Iron Man, Hulk, Thor, Ant-Man and Wasp have defeated some of the most dangerous Super Villains on the planet. But when the Super Villain prison system mysteriously shuts down, chaos is unleashed on the world. Earth's Mightiest Heroes must now band together as the Avengers to protect the planet from the threats that no single Super Hero could face alone. Their first task is to try and stop Graviton, a being whose power dwarfs anything ever seen. He's after Nick Fury, but will destroy the world to get to him. Individually the heroes have no chance, but together they can make a difference.

A CCTV classroom scheme ends up backfiring when the cameras are turned on the teachers. Grantly finds himself being helped by a familiar face. Janeece finally ends up confronting Ruby with the truth.

Kevin meets with Kathryn Tyler who decided the best way to get onto the property ladder was to design and build the house herself. Her idea was to build a house on a hillside plot in her parents' back garden in Falmouth but the plans were put on hold when Kathryn's father died. Kathryn is now ready to put the plans back on track and Kevin is there to monitor it's progress.

This week the two teams have to take over the running of a bakery and they are given a stall for selling their goods and also battle for the right to supply a hotel, a restaurant and a local coffee shop. One of the candidates from the loosing team is fired by Sir Alan at the end of the show.