It's a chilly morning at Camp Little Otter, which means summer is almost over. Buzz and Kip are excitedly packing their gear for the CIT overnight camping trip - it's a rite of passage when they'll write their names inside the lion's mouth. While Buzz allows that only the CITs that have gone before them know exactly what that means, he's planning on an intense night of bonding and survival and getting laid. He's not concerned about the details because he's read "The Secret," and he has put in a request with the universe. Equally excited, Grace stops by with news that Mack has made her an honorary CIT, allowing her to go on the camping trip too. When Kip suggests Grace might be able to help Buzz out with a little sex, Buzz wrinkles up his nose - they've known each other since they were three years old! Ew!
Marina is just promising Kip she'll tell Chloe about their relationship when Chloe pops up wearing giant sunglasses and a floppy hat. Declaring she's in mourning, she demands Marina sit next to her on the bus so she has a shoulder to cry on. The CITs gather round for Mack's yearly speech: after the bus ride, the CITs will make a 10-mile hike up Bear Mountain where they will make camp. This unchaperoned trip is the last test before they become official camp counselors! It's Robbie's day off, but he's agreed to drive the bus to the drop-off point so he can spend some time in town. It's a bittersweet moment for Mack when the bus leaves.
Since all the CITs are gone, Mack isn't thrilled when Cole asks for the day off. But when he insists he's in pain and has to go to the dentist, she lets him go. Roger stops by to let Mack know he has a crew clearing brush on their property border. Knowing Buzz is off on the overnight, Roger asks Mack if she wants to catch dinner at a new local restaurant. Figuring Roger has finally asked her on a real date, Mack says yes. Over at Camp Ridgefield, Sarah bumps into a former competitor, Kendra Huffington. Kendra is friendly and offers to train together - and why did Sarah quit swimming? Sarah confesses her whole sordid story or smoking pot, crashing into the tree, etc., and a friendship is born.
On the bus, Buzz and Grace are getting along like peas and carrots, while Chloe moans to Marina about Kip. Robbie pulls the bus over at the general store, making a last stop for supplies. Buzz isn't happy to spy some douchebags from Camp Ridgefield, who do their best to bully the Otters. Buzz grabs a couple of bananas and stuffs them into the tailpipes of the Ridgefielders ATVs before hopping back onto the bus. He screams "Ridgefield sucks!" as the bus leaves the bullies in the dust. Back at Little Otter, Mack tells Sheila about her date with Roger. She always thought he was an arrogant idiot, but now he seems like a good person. That's when Mack hears a chainsaw in the distance and takes off running... Roger told his brush cutter to fell her grandfather's massive chestnut tree!
Buzz puts himself in charge of the CIT expedition, so when the bus reaches Bear Mountain, Robbie hands him the CB radio to contact a ranger in case of emergency. Tomorrow at noon, the campers should face west and leave their names in the lion's mouth - whatever that means. Telling Buzz there's a case of beer waiting at the campsite, Robbie takes off, just as Zoe runs up to join the CITs, making a beeline for Buzz. Leaving Grace in the dust, Buzz winks at Kip, unable to believe his luck. His virginity has finally made the endangered species list.
Mack rushes to Camp Ridgefield to yell at Roger for cutting down her grandfather's tree. Roger is just explaining the tree had blight fungus and has to go when Mack spies Cole, who obviously didn't go to the dentist. Cole admits he lied and that he's talking to Roger about a job opportunity in Alaska. Furious, Mack cancels her date with Roger and tells Cole not to bother coming back to Little Otter, crushing both men. At a diner, Robbie bumps into hot French backpacker Veronique and her boyfriend Guilhem. They're looking for a specific waterfall, and when they fail to understand Robbie's directions, he offers to escort them there.
On the hike to the campsite, Chloe won't leave Marina's side. Frustrated, Kip asks Buzz to get Zoe to help, but Buzz refuses to let her go. At his wits' end, Kip decides to tell Chloe about his relationship with Marina, but Marina jumps in. After a moment of stunned silence, Chloe lets out a guttural scream of rage, then runs off into the woods. Not wanting to leave the trail, the other CITs charge Kip and Marina with going after Chloe. Self-proclaimed wilderness expert Buzz offers to be their guide, until Zoe asks who's going to set up the tent they'll be sharing...
Sarah's replacement Jay is screaming for Cole - the stove's broken! Insisting they don't need Cole, Mack turns a corner to find Sheila and all the little kids wearing head wreaths they made out of poison ivy. Declaring a lockdown, Mack sends Jay off to retrieve the calamine lotion and order 35 pizzas. Sarah meets Kendra for a workout. Kendra's jealous to hear that Sarah had an affair with Miguel; by comparison, Kendra's life sucks. Her mother is her trainer, so consequently, she has no time for a boyfriend.
Kip and Marina finally find Chloe, who insists Kip broke her heart. When Chloe claims they made love, Kip puts his foot down. Since Chloe was his first girlfriend, she'll always have a special place in Kip's heart. But she did blackmail him and threaten to expose his cancer, so he's done with the drama. Chloe has to stop crying and start walking because they have to find the others before it gets dark. Meanwhile, Robbie and the French couple reach the waterfall. Veronique immediately strips down and invites the guys for a swim. Robbie is shy at first, but finally gives in.
It's the end of another long day, and Mack plunks her white wine down next to a camp regular, Mr. Bendele. When Mack pats his hand, Mr. Bendele slumps over - he's dead! Since Jay disappeared and Cole's cheating on her with Roger, Mack calls Sheila, Todd and Raffi to help move Mr. Bendele's body someplace the campers can't see him. Roger finds Mack waiting for the coroner by the side of the road with a shrouded Mr. Bendele. Feeling sad, Mack admits there's been way too much change for her this summer: her grandfather's tree is gone, Sarah's gone, her marriage is over, Cole is leaving and her dad is losing his mind. Before long, she's crying in Roger's arms - and oddly enough, he's comforting her.
The CITs reach their camping spot and wilderness expert Buzz wastes no time leading the charge to set up. Back at Camp Ridgefield, Sarah's serving dinner when she discovers that Kendra has told everyone about the affair with Miguel - saying it resulted in genital warts! Sarah confronts Kendra, who merely orders another dinner roll. The French backpackers set up camp at the base of the waterfall and make tea. When Robbie's vision starts to go wonky, Veronique admits she made the tea from psychedelic mushrooms. Robbie is tripping - hard - and when Veronique and Guilhem invite him into their tent, he doesn't hesitate.
Buzz pulls Grace aside for a little talk. He's not having as much fun as he had hoped with Zoe; listening to her is way too hard. Grace tells Buzz not to pull out now - it would be a shame to waste the last 10 hours of sweat equity. Suddenly, Ridgefield bully Ryan and his bully buddies step out of the woods and begin destroying the camp. They single out Buzz. Three of the guys hold him down while Ryan starts punching. Chloe, Kip and Marina are just approaching the campsite when the Ridgefield guys run past them. They find Grace and Greg untying Buzz from a tree, his forehead scrawled with the world "BALLS" in Sharpie.
When Buzz runs off in tears, Kip chases after him. Buzz can't be comforted; his whole summer has been ruined. Finally, he agrees to let Kip radio a ranger to take them back to Little Otter. In Ridgefield's dining room, Kendra continues to order Sarah around, then comments on her poor attitude. Suddenly Sarah gets it - Kendra's worried Sarah's going to kick her ass in swimming this year. When Kendra loftily demands that Sarah get her mother's drink, Sarah pours it on her head, and a lively brawl ensues. It's not over until one of the other counselors pulls Sarah off Kendra.
Cole returns to Little Otter late that night to apologize for lying to Mack. She's just asking if he's going to take Roger's job when a ranger delivers Grace, Kip and Buzz, who runs for the bathroom. Half hysterical, Buzz scrubs his forehead wildly, refusing to talk about what happened. When Mack starts to get upset, Cole physically takes her outside. Mack needs to back off because, most likely, Buzz has to get the word BALLS off his forehead before he's ready to face her. Mack backs down, and luckily Cole knows the magic combination for removing Sharpie from skin. Pretty soon Buzz has calmed down and promises his mother they'll talk about everything tomorrow.
After Buzz goes to bed, Cole tells Mack he's going to work for Roger. He's taking Mack's advice and trying to grow up and build his future. Roger wants him to start right working away; it's a great opportunity for a nearly unemployable Cole. Mack gets it - but she hates it. The next morning Robbie wakes up next to the waterfall with a massive smile on his face. Mack smiles when Sarah shows up to ask for her job back. On the hike back to the CITs' camping spot, Buzz apologizes for blowing off Grace to spend time with Zoe. They meet up with Kip and Marina, and together, the foursome finally uncovers the mystery of the Lion's Head.
While the CITs enjoy a camp ritual, Robbie has a wild day off.