We're going back to the island where Total Drama began, for an all-new season with an all-new cast! Since Chris took the show worldwide, Camp Wawanakwa has been abandoned and turned into a toxic nuclear waste dump - the perfect place for a new season of painful, cringe-inducing challenges!

As the competition narrows down to twelve, the contestants now face a "Truth or Dare" type of challenge which forces the contestants to either embarrass themselves by saying the truth, or have their entire team be plunged underwater into shark-infested waters. During the challenge, Sam is revealed to have farted on his only date, Brick is revealed to have wet his pants on his first and last day of school one year, and B's full name is revealed to be Beverly. After a dip in the water in the midst of the challenge, Scott inadvertently begins a rivalry with Fang (a large, mutated shark with two legs) when, after he escapes certain consumption by him, he knocks out one of the shark's teeth in the process. The contestants then begin to bicker over the challenge, until Chris decides to cancel the challenge and move them into an even more dangerous one. Throughout the episode, Mike continues his growing relationship with Zoey, while it seems that Sam is also starting a relationship with Dakota! The second challenge is a relay race where the teams must each carry their "team mascot" across an obstacle course. Scott tries to move along his part of the relay very slowly to hold the Toxic Rats up and thus throw the challenge, but is unsuccessful. Mike reveals another personality that turns him into a highly skilled Swedish gymnast named Svetlana. Zoey, meanwhile, escapes becoming lunch to two giant, mutated beavers by kicking them both in their kiwis. In the end, Cameron wins the challenge for the Mutant Maggots, and the Toxic Rats face elimination again. Due to Dakota being distracted by fame throughout her entire time in the season, she is the one who gets eliminated next. There were no cameos in this episode.

The episode begins with everyone eating at the cafeteria. In there, Mike tries to explain his personality problem by telling everyone that he is role playing, but then admits his disorder at the confessional. The contestants are then taken to the first challenge: to climb up a mountain to the top with your bare hands and feet, or by using stuff from a junk pile that is owned by a giant mutated cockroach. Once they are climbing the mountain, they must avoid the stuff that Chef throws at them. The Toxic Rats manages to get to the top of the mountain first by slingshot-ting themselves on a sofa to the top, winning the first challenge and getting them an advantage in the second challenge: a "Capture the Flag" type of challenge where each of the teams own an ice castle in a snowy area, and must destroy each other's castles (either by melting or by snowballs) in order to capture the other team's flag. In the end, Mike's Svetlana personality manages to capture his team's flag and win the challenge, but before you know it, another of Mike's personalities is revealed that is an egotistical hero named Vito who Anne Maria starts to like this personality from Mike. In the elimination ceremony, Scott sets up B in order for everyone to vote him off, succeeding in the process. Dakota then returns after her father complained that she was unfairly voted out. She now becomes an intern on the show and does not compete for the million dollar prize. B is then voted off. There were also no cameos in this episode.

The ten remaining campers compete in a spooky themed challenge where all of them are taken to the forest and must navigate their way to a cemetery, dig and open up a coffin, grab a flashlight from inside the coffin and find their way around the forest while racing to the finish line. Throughout the challenge, they encounter several mutated animals and eventually a giant pink spider that attacks and captures all of the contestants except Mike, Cameron and Anne Maria. Due to Mike's severe disorder, his Vito personality continues to attract Anne Maria and soon causes her and Mike to get together, without Mike remembering about Zoey. At the end when they are going to fight the giant spider, Zoey sees Mike and Ann Maria kissing and starts to get jealous (this is where the love triangle begins). As for everyone being captured by the giant spider, thanks to Cameron and Svetlana, both of them rescue everyone from the giant spider and save the day. However, the Rats win the challenge instead and the Maggots lose for the first time. At the end when Cameron defeats the spider, it is revealed that the spider was Izzy all along inside the giant spider costume. At the campfire ceremony, Brick votes himself out because he left his team behind and failed his code, but Chris unveils that the person who is voted out that night will be on the other team tomorrow, meaning Jo and Brick will be battling it out on separate teams. With no one to throw, Dakota (who is an intern on the show) takes the hurl of shame by Chris saying she can swim back.

The Rats aren't getting along with Brick, and neither is Jo, who accuses him of switching sides. Meanwhile, Zoey is mad at Mike for his weird "characters" and ditching her for Ann Maria. And after the campers' personal items start disappearing, suspicions are running high all over.

In this episode, both teams face off in a fashion contest by finding models on the island, also saving Lindsay, after she is kidnapped by Sasquatchinakwa. Scott's rivalry with Fang heats up after he tricks him into falling into one of his own traps, and he later tries to sow some seeds to get Zoey eliminated in the future. Sam goes on a video game frenzy, which almost wins the challenge until Jo, in an anger trip from her looks being laughed at, punches Sasquatchinakwa to save Lindsay and win the challenge, leaving the Rats to vote off Sam. Before Sam is hurled off, Dakota gives him her number until he loses it. Also, Jo and Scott, after volunteering themselves as their teams' strongest members, are asked to switch teams, placing Jo on the Rats and Scott on the Maggots.

The two teams are sent into an abandoned mine, where Jo takes charge of the Rats, and Mike's disorder gets more out of hand when a fourth personality: Manitoba Smith, makes his debut. Meanwhile, Brick throws the challenge to save his the Maggots, as they were his original team, resulting in another loss for the Toxic Rats. Meanwhile, a still-feral Ezekiel falls in love with Anne Maria, and wins her over by giving her a diamond-like gem. In the end, Brick is voted off for throwing the challenge and Anne Maria quits the competition, thinking she'll be rich with the gem she's received, but later finds out that the gem is made of cubic zirconium, making the gem worthless. She tries to get back into the game, but gets hurled along with Brick. With Anne Maria gone, Chris decides to let Dakota back into the game and places her on the Mutant Maggots.

The campers wake up far from shore, floating on rafts. And new Maggot team member Dakota is starting to mutate, getting taller as her hair grows back ridiculously fast and bright orange to boot. Chris and Chef jet ski out to explain that the challenge has already begun! First, teams must get to shore by any means possible, avoiding the giant mutant squid if they can. The race is on! The squid soon starts to attack Jo and Lightning, who make a deal to work together and go all the way to the finale. Fang sniffs out Scott and leaps onto the Maggots' raft to battle him! Then Dakota accidentally draws the squid's attention and it starts attacking the Maggots, while Jo and Lightning race for shore. Inspired, Cameron gets the squid to slam down one end of their raft, and the Maggots sail over the Rats' heads to land on the beach first. Phew!

It's merge day! No more teams, just each competitor fighting for survival! To celebrate, Chris crushes the extra team cabin with a pile of concrete left over from building Mt. Chrismore, his giant monument to himself. Cameron tries to form an alliance with Jo, but gets rejected. She's already got her ally: Lightning! Meanwhile, Scott has learned of Mike's multiple personalities and uses this info to blackmail Mike, forcing Mike to help him through the challenges. Otherwise, Scott will tell Zoey all about Mike's little secret!

It's down to the final five. With the strongest players now the most likely to get voted off, Scott and Lightning are both serious contenders for the Hurl of Shame. Meanwhile, Lightning is gunning for Jo after shem turned him into shark bait. Zoey is determined to take down Scott for what he did to Mike. Cameron agrees to do Jo's bidding, hoping she'll protect him from everyone else.

The hardest challenge yet is presented to the contestants after Chris steps into one of Scott's snares.

The final three contestants take part in a hike through a forest filled with mutated plants and animals in search for a rare flower.

The final two contestants battle for the $1 million grand prize.