The final five teams race in Edinburgh, Scotland, where a double U-turn puts two duos in jeopardy.

Homer is recruited to be a church deacon by the trendy new reverend in town (guest voice Norton). But Bart asks Flanders to help him track down their former pastor, Reverend Lovejoy, when Homer starts to embrace the faith a little too seriously.

Meanwhile, Marge finds out her dry cleaners mistakenly swapped her wedding dress with one of Krusty's costumes.

Regina comes up with a plan to use a failsafe built into her curse to destroy Storybrooke and its residents while she and Henry escape to the Enchanted Forest. When Henry rejects her, Regina turns to Hook... who has allies of his own. Meanwhile, in the fairytale world, Regina has Rumpelstiltskin disguise her as a peasant so that she can find the renegade Snow and kill her.

While accompanying Tina to a "Boyz 4 Now" concert, Louise develops a crush on one of the lead singers, Boo Boo - and is in disbelief that she actually likes a boy! Meanwhile, Gene gets creative - and slightly offensive - in a table-setting competition.

Stan is shocked when he is told that Deputy Director Bullock is showing early signs of dementia and needs his memory erased; Roger hires an old friend to help Steve with a bully at school.

With just six All-Stars remaining, the teams are asked to write, produce and direct a demonstrational video to highlight LG's Smart Home and Home Entertainment systems. One Project Manager's runaway concept leaves the team with little choice but to follow their leader, while the other team gets too caught up in small details.

After teddy bear Rupert gets recalled, Stewie stops at nothing to get back his beloved best friend. Meanwhile, Peter falls ill and can't compete in his bowling tournament. So Lois fills in for him. But when she gets a little too close to Peter's teammates, he gets jealous.

Despite their best efforts, the tribe falls short of their fundraising goals for Claudia Joy's garden until Gloria discovers Holly has a hidden talent that could help them. Hector finds out about Gloria and Patrick. Michael unknowingly encourages Kat's daughter Hannah, a Citadel cadet, to switch from Air Force to Army.

After their custody meeting, Jackie rear-ends Kevin and wakes up as a patient in her own ER. Kevin accuses her of using. Coop begins covering for Carrie and taking on a lot more work. When Carrie checks on Jackie, she writes her a prescription for Oxy, unaware she's an addict. The most unlikely person asks Jackie out on a date.

On the night of Peter's gubernatorial election, Alicia, Will and Diane race to a series of emergency court proceedings when Zach believes he's witnessed vote tampering. Meanwhile, an unlikely source offers Cary aid to start his own firm, while the conflicted feelings Alicia has in her personal and professional lives come to a head.

In King's Landing, with the help of Littlefinger, the Lannisters discover the Tyrells' plot to marry off Sansa Stark to Loras Tyrell. To prevent the union, Tywin Lannister plans to marry Sansa to Tyrion, and Cersei to Loras instead, despite Cersei and Tyrion's protests. At Dragonstone, Stannis visits his wife, Selyse, to confess about his infidelity, only to realize that his wife has always known and approves it. He then reveals to his daughter, Shireen, that Davos is imprisoned, and she sneaks into the dungeon to visit him and teaches him to read. In Riverlands, the Hound defeats Lord Beric in trial by combat and is released, angering Arya Stark. Gendry decides to stay with the Brotherhood, and Thoros and Beric plan to ransom Arya to her brother, Robb Stark. At Riverrun, despite many objections, Robb Stark decides to execute Lord Karstark after he murdered two captive Lannister boys. With the Karstarks abandoning him, Robb plans to make a desperate alliance with Walder Frey. Beyond the Wall, Jon Snow struggles to earn the Wildlings' trust while holding back the imperative information. Later, he and Ygritte have sex. Across the Narrow Sea, while on the march, Daenerys Targaryen's Unsullied select Grey Worm as their leader.

Desperate to find Padma, Emily, Aiden and Nolan must track down the Falc0n's true identity and put a stop to the Initiative while Emily struggles with her future and Victoria fights her own battle after a very exposing interview on 'Nightline'.

Kiera and Carlos's reunion is a bumpy one as they attempt to thwart Liber8's brazen hijacking of a prison transfer. Meanwhile, Kellog approaches Alec with an enticing partnership proposition. The young genius is tempted, but will it lead him down a dark path?

Shelby finds a legendary old grave site and the crew has an accident. Big Gun has yet another yarder accident and Levi decides to make some major crew changes. Brad and Swilley are the victims of a prank and they lose yet another assistant. Joe and Coatsy are having a tough time keeping steady work, while at Rygaard, Craig and Gabe attempt to bury the hatchet, and Dave is forced to eat some humble pie.

The public face of Colombia has changed immensely over the past ten years and is still changing for the better. Tony will explore several regions of the country from the mountains down to the Caribbean coast to the coca leaf growing inlands formerly controlled by drug cartels.

Set among the events surrounding Martin Luther King's assassination, Peggy tries to get a new apartment, Ginsberg is set up on a date, and Don has a revelation during his weekend with the kids.

J.J. LaRoche personally requests Jane's help when the mysterious container he's been hiding for nine years is stolen from his home.

As the purged Cardinals are dismissed and stripped of their titles and wealth, one of them angrily sets the Vatican treasury ablaze. Incensed by the new King Ferdinand's arrogant refusal to accept Giovanni as Lucrezia's child, Cesare travels to Naples to fix the problem. After Lucrezia and Alfonso's wedding, Alfonso realizes that the political sands are shifting - and not in his favor. Upset, he abandons Lucrezia alone on their wedding night, driving her into the arms of someone else.

As a hostage crisis in Uzbekistan heats up, Selina and Secretary of Defense General Maddox have trouble getting on the same page at their joint appearance at the Marine Corps Base at Quantico. Sue testifies at a congressional hearing on governmental efficiencies; Dan and Gary jockey for the Veep's ear.

As Riley struggles with her marriage and recent decisions at work, she and Lacey decide to attend church with Georgia and Harold. Also, Harold plans a romantic gesture for Georgia. Kyle prepares to testify against his former employer and gets guidance from his lawyer, Graham. Meanwhile Selena warns Derek about his overzealous client Lisa, but reveals more about herself in the process than she intended. Evan takes his first real step moving on from Riley when he and Shelby have their first date.

Marta discovers the painful truth about the identity of Natalie's kidnapper and learns a compelling new piece of information about her husband's murder. Meanwhile, Gabriel takes dangerous matters into his own hands, and Kat and Ramos rekindle their illicit relationship.

At the behest of King Horik, Ragnar assembles a small party to travel to Gotaland (modern day Sweden) to resolve a land dispute with the area's leader, Jarl Borg. Ragnar's renown precedes him and Jarl Borg is intrigued - has he found a new ally or is Ragnar just a puppet of the king? Meanwhile in Kattegat, with a plague taking its toll on the village, the people look to Lagertha to help appease the gods.

Air pollution is now second only to smoking as a killer in the UK, yet as a nation we are failing to meet targets on reducing emissions. The team investigate what air pollution is, where it comes from, and what it is doing to us.

Jem Stansfield reveals that cleaner-looking air doesn't necessarily mean healthier air; and he demonstrates why modern diesel engines, in spite of their growing green credentials, may be bigger polluters than petrol.

Maggie Philbin follows some typical commuters to reveal how much pollution we all actually breathe in, and she also finds out how a soap powder additive could turn all our clothes into personal pollution filters.

And while people continue to worry about the health of their lungs, Liz Bonnin investigates new research that suggests it may be our hearts that are more at risk from air pollution.

Freddie and Stuart are hosting a wake to mark the passing of an old friend. As they are joined by their small circle of elderly chums, the couple manage to create a toe-curlingly awkward evening with very little food but plenty of bitchy insults. Their new young upstairs neighbour Ash - whose sexuality becomes a point of great debate - spends the evening attempting to be the perfect guest, while fending off the advances of Freddie and Stuart's best friend Violet.

Manager Trish is struggling to keep things running smoothly. She has a world-of-work seminar to run, the temp is late, and difficult employee Angela returns, fresh from winning a tribunal. Karl is the only member of staff Trish can rely on, but now even he's reached the end of his tether.