Plot
Twin sisters, Shane (Mary-Kate Olsen) and Elizabeth Dalton (Ashley Olsen), live separately from one another on opposite ends of the country after their parents divorced years earlier. Shane, who lives with their mom in Los Angeles, is a chilled out, tree-hugging vegetarian who is very into nature and spiritual beliefs, while her estranged sister Lizzie, who lives with their dad in Washington, D.C. is a level-headed grade A student with a driven personality. However, unknown to each other, they both apply to be contestants on a reality game show filmed in Mexico called The Challenge, which tests contestants strength and survival skills in various challenges as they work as part of a team in order to win college scholarships.
Marcus, (Brian Skala), the head intern at "The Challenge", informs the show's producer, Max (Joe Michael Burke), of their distant relationship. Knowing they dislike each other, Marcus puts both girls on the same team, Team Mayan, as part of a scheme to boost the show's ratings. Backstage, Shane meets and becomes close to Adam (Lukas Behnken), a laid-back jock who is put on the opposite team, Team Aztec. Team Aztec also includes Kelly (Sarah Bastian), an overly-competitive swimmer, JJ (Diana Carreno), a ditzy "triple threat" with dreams of stardom, and Charles (Ty Hodges), a calm and intuitive city boy who plans to study psychotherapy. Along with Shane and Lizzie, Team Mayan also includes Anthony (Theo Rossi), an Italian-American food enthusiast, and Justin (Zakk Moore), a surfer and skater from sunny Florida. At their first meeting, Max informs the group of the rules, which include a prohibition on romantic entanglements between contestants, as it can result in disqualification from a challenge.
During the first challenge, Shane and Lizzie's bickering prevents them from working together, and Team Aztec wins the points. When Anthony and Justin make them realize that they'll need to pull together, they start putting aside their differences for the sake of the team. Over the first few days, Shane and Adam become more and more close, and Kelly suspects something is going on. At the same time, Lizzie starts hanging out behind the scenes with Marcus, although he is still being asked by Max to spy on the girls. Marcus finds out that Shane hates heights and that Lizzie is afraid of snakes, information which Max plans to use later on. Team Mayan win the fourth and fifth challenges, making the score 3-2 to Team Aztec, and Shane and Lizzie both start to respect what the other knows.
One night, the girls sneak out to meet Marcus and Adam; but they're followed by Max who fails to get video footage of their meeting. However, Kelly manages to take a picture of Adam and Shane kissing and shows it to Max. He disqualifies both of them from the next round, which Team Mayan eventually win, tying the score of the teams involved in "The Challenge". Team Mayan is given a boat party as reward for their victory, which Team Aztec have to cater for in costume. At the party, Marcus tells Lizzie that he's been behind Max's troublemaking, and she dumps him. Later on, Shane and Lizzie manage to patch things up with each other for good after realizing that they're not all that different from each other.
The final challenge will decide the winners of "The Challenge". It is an assault course featuring various challenges including walking harnessed on a bridge high over a canyon (incorporating knowledge about Shane's established fear) and then walking on narrow planks over a pit of snakes (reflecting Max's knowledge of Lizzie's fear). The girls help each other out and Team Mayan reaches the totem before the others, making them the winners. All of the contestants receive college scholarships. With the experience coming to a close, Kelly apologizes for the mistakes, Lizzie makes up with Marcus, and then the girls retaliate against Max by tipping slime on him while taking a picture.
The Challenge was Mary-Kate and Ashley's last direct to video production, so in a short scene at the end of the movie, some of the twins' boyfriends from past movies and TV-shows show up and begin arguing over who the girls loved more. This leads to the girls leaving together while saying, "Boys may come and go, but we'll always have each other—and that's not just in the movies."
