Twenty-eight Challenge competitors arrive in Costa Rica only to find out that they will be teamed up with their biggest rivals. And a fight on night two sends one Challenger home early.

A strong team struggles on the girls' elimination day.

The guys plot to send CT home, while Laurel and Mandi vie for his attention. Also: Kenny worries that he's lost his competitive edge.

Things get heated between teammates Jasmine and Jonna, and a blowout between the girls changes the game. Meanwhile, Adam pursues Jenn.

Evan considers throwing a challenge as part of the guys' plan to get rid of CT. Meanwhile, CT finds himself in the middle of a love triangle with Mandi and Laurel.

One alliance begins to crumble after a brawl between Jenn and Cara Maria. Later, a surprise twist changes the game.

Some players crack under pressure as the final challenge approaches; Laurel defends Cara Maria after Wes and Paula drive her to tears.

Two strong male teams fight tooth and nail in "T-Bone," the last elimination of the season. A clue sends the remaining twelve Challengers off to another destination, where they begin the toughest Final in Challenge history.

With the Final underway, teams thrive or fail based on their ability to work together. One male team and one female team will claim the title of Challenge champions.

The "Rivals" cast reunites and dishes about what went down on the 21st season.

Outtakes and previously unseen footage for the 21st season.