The Treasure Island of Dr. McLean

'''The teams wake up in the middle of the lake, where a returnee starts mutating due to a toxic exposure, and seeks help from a fellow teammate. Meanwhile, another member tries to help a friend keep his secret under control. Someone reveals to have found the idol, and asks someone else to keep it a secret. The finder is eliminated, but uses their discovery and new friend to eliminate a mutant instead.'''

Plot
The episode begins when both teams are seen sleeping on rafts out in the lake. Scott doesn't seem to remember anything after dinner. Cameron goes into a flashback when being served the "Turkey Butterlini". Chef tells Cameron to enjoy his nap, then corrects himself and says meal. Mike then finds a fedora hat and puts it on, which makes him transform into Manitoba Smith and starts to talk to Zoey. Cameron pushes her in the water and takes off the hat for Mike, in order to save their relationship. He then makes a confessional about how he helps Mike with his disorder, and in return he helps him get rid of Scott. He also knows all the ways Mike goes into his different personalities, but hasn't mastered getting his original one yet. Dakota also makes a confessional. She states that now being bald, she has to focus on becoming friends with the rest of the competitors. She chooses Zoey as being the best choice to be seen out in public, post-makeover.

Chris then arrives to start the next challenge but Dakota interrupts him and starts revealing embarrassing things she learned about Chris while being an intern. However no one pays attention as Dakota grows larger and her hair started to grow back, only that now in a neon green color. Chris then gets on with the challenge saying first that the Chris immunity statue has been found, and that the teams have to first race back to shore to earn a reward to use for the second part of the challenge. While rowing, Lightning runs into a mutated squid, slowing down the Rats. Meanwhile, Fang the shark has found the Maggots, but Dakota punches it with her new strength into the squid's eye, releasing the Rats free from its tentacles. When the Maggots finally reached where the squid was, it starts attacking them. Cameron then comes up with a plan to hit the front of the board launching everyone on the back to shore.

Once ashore, Dakota starts to look for Chris and is already seen even bigger than before, and starts to jump for Chris in the helicopter. He dumps the rewards the Maggots won to them, a compass and a map of the island. Lightning and Jo are seen washed up on shore as Chris continues saying that now the teams have to find the chest in which Gwen is buried alive in, along with Sam, who was knocked out by the meal the night before as well. Once seeing Sam knocked out, Dakota becomes angry and grows even more, turning orange, and growing a tail too. Chris allows the Maggots to head out, but stops the Rats. He gives them the "Penalty Belt" and gives them a metal detector. Jo states how that would be of any use to them as the chest is made of wood. Chris thent states it would not and sets them off.

Back in the chest, Gwen tries to call Chris. He answers and makes fun of the farting noise in the background from Sam, which knock her out. In a swamp near by, the Maggots reached the shores of it. Mike finds a path out of the swamp and Cameron and him start to swim. Scott then tries to make his team lose by showing the way through the swamp for the Rats. Dakota then grabs Zoey and starts for the water. Scott then says Sam is losing air in the chest, which makes Dakota drop Zoey and race for Sam, leaving Scott and Zoey alone. Scott says he trusts Zoey enough to show that he has the immunity statue. Zoey is flattered by the fact he trusts her that much. He then tells her at least he doesn't hide things from her like Mike, and tries to make it seem like he is the only trustworthy person on her team, then they both go into the water. Later on, the Rats finally make it to the swamp. Jo sees the arrow Scott made and follows it through the water. Back on the Maggot's team, Mike and Cameron try to tell Zoey not to trust Scott, but Zoey says he's not that bad, and doesn't notice when she walks onto the back of a giant alligator, which startles her and her team, making them run for a nearby tree. Scott and Cameron climb up, while Mike turns into Svetlana to get up, leaving Zoey by herself. She screams for Mike and he turns back into himself, which Cameron figures out is how he gets Mike to change into himself and grabs for her. Dakota then fights with the alligator to save her team. They try to find their way out of the swamp, but the map was destroyed, Zoey then asks for the compass, but Mike couldn't find it. Scott then shows in a confessional that he had the compass and tries to hide it. Lightning then sees Dakota fighting and brags about how he could do the same, to more alligators show up and start attacking him. Cameron then tries to find an alternative to help them out, which was looking at the moss on the trees and points towards a thorn forest, and Dakota clears a path while fighting. Mike's shirt is caught on one of the thorns, turning him into Vito, and calls out for Anne Maria. Zoey stops and seems upset of hearing Vito again, but Cameron tries to pull his shirt back down. Jo and Lightning both get out as well and find a key under a rock with the metal detector, one for the belt lock, and one for the chest. Jo then hears Gwen underground and starts digging, while Scott tries to make his team dig away from the actual location of them, but Jo had already found Gwen, making the Rats have their second win of the season. Dakota then reaches for Sam in the chest, and Sam wakes up to her cuddling him. Sam then says in the confessional that he thinks Dakota has gotten even more awesome.

Later that night, at the campgrounds, Dakota and Sam are seen away from the rest of the Maggots, while Mike pulls Zoey over to say they need to get rid of Scott, but Zoey still didn't know who to vote for. Scott tries to get the secret about Mike by saying to Cameron that he appreciates that he helps him. Cameron didn't know it was a trick and tells him Mike has multiple personality disorder.

At the elimination ceremony, Dakota first asks if Sam still likes Dakota, Sam says he'll always like her, and they make out, disgusting the other campers. Chris then tells that the camper voted off was Scott. He then pulls out the Chris idol, making Chris go to the next highest voted person, which happened to be Dakota with one vote, from Zoey, who didn't like her friendship that could potentially hurt her health. Dakota doesn't seem to care anymore about the show by being too occupied by Sam and takes the Hurl of Shame.

Quotes
Zoey: No! Chris must've set us adrift when we went to sleep! Scott: Yeah...wait, I don't remember anything after dinner. Cameron: Dinner. That's it! (has a flashback) Cameron: (in flashback) Eww...what is this? Chef: Turkey Butterlini. Enjoy your nap. I mean, meal (laughs; flashback ends) Cameron: Turkey makes you sleepy, so mutant turkey must've knocked us out cold!
 * Mike: What? Where are we?
 * Dakota: I'm going to turn you into a purse!
 * Dakota: (hurting the alligator) Why you hit yourself? Why you hit yourself?
 * Lightning: (to crocodiles) Uh... Sha-friends?
 * Dakota: Uh-hahaha, me got munchies!
 * Zoey: (after Dakota's elimination) Her friendship was hazardous to my health. I had to vote her off.
 * Dakota: (to Zoey) Come on, ba-fa-fa!!!
 * Zoey:  Ba-fa-fa?
 * Dakota: Short for BFF!
 * Scott: Oh man, Sam is probably suffocating right now! (grins)
 * Dakota: (shocked face) Sam, I'll save you!!
 * Mike: (as Vito) Put yo hands up! Put yo, put yo hands up!

Continuity

 * This is the second episode in the season in which the Toxic Rats won. The first was Finders Creepers.
 * The is the first time in which all four of Mike's alternate personalities appear in the same episode.
 * Gwen makes a cameo in this episode.
 * This marks the first time Gwen has lines since Aftermath Aftermayhem.
 * With her cameo, the final two of Total Drama Island have both made a cameo at one point during Total Drama: Revenge of the Island.
 * This is the second episode Gwen has to face her worst fear, the first time is in Phobia Factor.
 * This also shows that Gwen hasn't fully conquered her fear from the first season.
 * This is the first episode that Dakota has worn her original outfit since Ice Ice Baby, as she had to wear an intern outfit from Finders Creepers through A Mine is a Terrible Thing to Waste.
 * Sam returns in this episode as part of the challenge.
 * This makes him the second contestant this season to return to do something other than be a contestant. The other being Dakota.
 * This is the second time the contestants woke up somewhere in the middle of the lake. The first time is in Camp Castaways.