Part 1 of 2. The Northeast regional qualifying round challenges the athletes.

The key to understanding the universe seems to be understanding its smallest components. But reconciling the two has proved to be a tremendous scientific challenges as the behavior in the quantum realm bears little resemblance to the universe we know. This program explains some of the strange behavior scientists have discovered at the smallest scales.

Conclusion. The Northeast regional qualifying round challenges the athletes.

Janelle wants to open a gym; Meri talks about her fertility problems; the family look into separate mortgages in a bid to acquire adjacent homes.

What's the most awkward day of the year for a Polygamist? Valentine's Day! And how do the Browns handle monogamy's biggest holiday of love? This year, Kody takes his young daughters to a daddy-daughter Valentine's dance at their school.

Adam and Jamie determine if a person wrapped in bubble packaging could survive a fall from a building. Also: Ejection-seat experiments are conducted.

Cruz takes revenge on Jackie's coworkers for their history of covering up her addiction; Eddie offers support for Jackie's case during his deposition to Kevin's lawyer; O'Hara finally leans on Coop during an OB/GYN appointment.

The fourth season begins with Jane and Owen's Italy trip being interrupted by Kim, who wants her to return home to take on a lucrative murder case. Meanwhile, Stacy seeks advice from a relationship guru.

When Jim and Carlos investigate the death of a millionaire who bequeathed all his wealth to an organization of UFO enthusiasts, the organization's leader accuses the FDLE of covering up the true cause of death: an alien abduction. Meanwhile, Jim and Callie's relationship heats up, but Callie's job search to keep her in Palm Glade falters.

Tyrion awakens to a changed situation. King Joffrey doles out rewards to his subjects. As Theon stirs his men to action, Luwin offers some final advice. Brienne silences Jaime; Arya receives a gift from Jaqen; Dany goes to a strange place; Jon proves himself to Qhorin.

After returning to the casino, Sarah and Holder find themselves on the run. Stan and Richmond must make life-altering decisions that will decide their fates.

Kiera has found her way home, at the cost of a truce with Liber8.

The Ice Road Truckers battle across the continent over frozen lakes, rivers, and ocean. Alex heads farther north than ever before on the deadly Dempster. Hugh and Rick face an impossible task on the thin ice of Manitoba's Winter Roads. In Alaska, veteran Jack Jessee returns to lead a pack of hungry new drivers on Carlile's biggest mission in history.

Cathy pays back Maxine and Dave, and confronts Joy about Paul; Sean discovers the pros and cons of his relationship with Tim and Giselle; Paul learns something new about Cathy.

Athletes who completed the Northeast region preliminary round take on a more challenging course in their bid to qualify for the national finals in Las Vegas.

Ashton Kutcher is the guest host. Prank victims include Kim Kardashian and Drake.

Lane's shameful secret comes to the surface with dire consequences. Don recaptures his hunger for success, and Sally experiences a major milestone.

Upon his return to Rome, Juan spins an elaborate yarn about how he received his "battle wounds", but Cesare is unconvinced and determined to learn the truth. Meanwhile, Lucrezia takes a lover, the younger brother of her intended; and Della Rovere recruits an accomplice for his assassination plot.

Lydia goes missing from the hospital and both werewolves and hunters try to find her.

The vice president's office takes some heat over a pregnancy rumor and the firing of a Secret Service agent, so Selina establishes some new ground rules about internal correspondence. Meanwhile, Dan tries to cover his boss' tracks on the clean-jobs bill; and a staffer's job may be in jeopardy.

Tensions grow between Riley and her co-worker, Selena, when Selena and Evan begin dating. Riley considers the lack of a male role model in the house when her son, Travis, gets caught in a "curious situation" with Taylor's daughter. Riley lends advice to one of her clients, a rodeo cowboy, when his relationship hits a wall. Linette tries to compete with Taylor when she applies for a loan to buy the salon.

Struggling since his wife's death and at the urging of his daughter, Longmire knows that the time has come to turn his life around. With the help of a female deputy new to the department, he becomes reinvigorated about his job and committed to running for re-election. When an ambitious young deputy decides to run against him for sheriff, Longmire feels betrayed but remains steadfast in his dedication to the community.

Jessa and Marnie meet an eligible bachelor who is not all he seems and Hannah gets more involved in Adam's life.

Eric Andre and Hannibal Burress were joined by Tatyana Ali.

The band's new female producer sends them on a vacation to help write songs for the new album. The getaway proves anything but relaxing, however, when they end up in a brutal country and are sold into sex slavery.

The contestants arrive in Tasmania for a market stall competition, where they are divided into four teams. The teams must run their own take away market stall and create their own unique dish.

Princess Bubblegum is concerned over her mortality and reveals her designated successor to Finn and Jake.