Larry Wampler is desperately trying to convince his indie loner son Kip that he's going to love being a CIT (counselor-in-training) at Little Otter Family Camp for the summer, but Kip isn't too sure. He steps out of his dad's car and gets lost in the vision of luscious fellow CIT Marina - just as a random fishing hook snags his nose ring. Later, Little Otter owner and director Mack Granger welcomes the returning campers in the dining hall, presided over by counselor Sarah Brennan, who for years now has had a summer romance with fellow counselor Robbie Eisenberg. Having recently split with her husband Steve over his affair with Russian esthetician Ekaterina, Mack is a little off her game and struggling to keep it together. So when she hears that brown sludge that smells like poo is flowing out of the showers, it's not really a surprise.
While investigating the sludge problem, camp handyman Cole, a laidback force of nature, asks Mack what happened with Steve - when did they stop having sex? Mack admits her life changed when she had her son Buzz, whom she sees as a fragile, sensitive soul who really needs his mom. In reality, Buzz is planning to lose his virginity at camp this summer - until Robbie assigns him to work with the little kids in Toddler Town. Handsome Aussie Roger Shepard, director of the successful Camp Ridgefield franchise, stops by to gloat, offering to buy Little Otter from Mack now that she's single. Insisting that the day she sells to Roger is the day she declares her life a failure, Mack sends him packing, just as the broken pipe begins to spurt in earnest.
Hoping against hope, Buzz asks Mack if he can move into Boys Town with the other CITs, but she refuses - they need to stick together as a family! Down at the lake, Sarah tells Mack that she gave up swimming, which is what got her a scholarship to Stanford. With his nose freshly bandaged, Kip takes out a raft, which is quickly overtaken by Buzz. Marina tries to make friends with some of the other girls, but they're icy - perhaps they saw the topless photos of her that went viral and obliterated her reputation at school? Spying the girls, Buzz does a "float-by," hoping to score points. His delivery goes over like a lead balloon, drawing sighs from Kip and the girls, but Marina's not judgmental. Oblivious and confident, Buzz recruits Kip for a trip to buy condoms.
At the General Store, Marina introduces herself to Kip, while camper Grace shops with her two dads Raffi and Todd and little brother Fyodor. She spies Buzz buying an enormous box of condoms, just as Ryan, a bully from Camp Ridgefield, picks a fight with Kip, who's soon emasculated once again. Later that night, Marina hangs out with Kip while most of the campers learn the Wobble. Kip's not a joiner, but Marina doesn't know what kind of person she is, so she jumps in, just as Mack's ex shows up to demand she sell Little Otter. Steve is learning how to love again, and Ekaterina wants a kid. To add insult to injury, Steve invites Buzz over for dinner.
That night, the CITs are hanging around the campfire when Marina finds Kip again, and Robbie and Sarah reignite their relationship. Sarah confesses that she quit swimming because it wasn't fun anymore. After getting high, Buzz tells Marina and Kip about his dad's relationship with Ekaterina, which he doesn't think will last long because of their 20-year age difference. Meanwhile, Kip is clearly falling for Marina. The next morning, Sarah leaves Robbie in bed to take a swim in the lake. Unfortunately she doesn't notice a canoe heading in her direction and smacks into it. The handsome oarsman pulls her into his canoe, promising first aid. Meanwhile, Mack's at the bank talking to loan officer Glenn Reed. Since she's still paying off loans made to her father, another one won't be approved.
The handsome oarsman takes Sarah back to his villa at Camp Ridgefield where she learns he is Miguel Santos, author of her favorite book, "The Heart Is an Arsenal." Sarah finds herself confessing the real reason why she quit swimming: there was an incident involving pot, booze, her car and a flagpole, which put the kibosh on her scholarship. After a little flirting, Sarah heads off to work - it's Circus Day! Mack is in her office donning a pink wig when Cal stops in to ask how things went with Steve last night. Mack contends that he doesn't want to hear "the kind of thing you've designed your life to avoid," and heads out to Circus Day.
Circus Day is well underway when Grace asks Buzz if he used his box of rubbers yet. Mack shows up just as Buzz is embarrassing himself in front of Grace, using the word "faggy." Did he forget that Grace's dads are gay?! Insisting they need to talk, Mack chases him down to the dock. In an effort to get his mother to back off, Buzz claims his dad traded up to Ekaterina, which so infuriates Mack that she pushes Buzz into the lake. That night, Roger accosts a drunken Mack at the local dive bar. When she confesses to pushing Buzz off the dock, Roger tells her Ekaterina is horsey. Moments later, Mack and Roger are doing it in his car.
The next morning, Mack has a crushing hangover and crushing guilt. She confesses her dalliance with Roger to Raffi and Todd, claiming she was exorcising Steve. She saw colors, then went right back to hating Roger, who probably knows it was a one-night stand. Mack takes off to shut down her affair with Roger, but they wind up having sex on his desk. Meanwhile, Robbie visits Sarah in the kitchen to inform her that he got accepted to Stanford. Sarah doesn't take the news well, claiming that it's more pressure than she needs, and besides, she's really busy.
Buzz, Kip and Marina are shooting hoops and eating popsicles when Ryan and his buddies motor up on their ATVs. When Ryan makes a lewd comment to Marina, Kip swings into action. He's thrilled to land his first punch on Ryan's jaw, but it's not long before he's in Mack's office with a black eye. Kip insists he's going to call his dad to pick him up - he's done with camp. He knows his dad is worried, but if Kip's leukemia comes back, it comes back; Kip can't let it run his life. Mack congratulates Kip on punching Ryan, promising that if he stays at Little Otter, he'll probably have many more terrific days, minus the shiner.
Sarah calls Mack to the lake to deal with an emergency: some of the Camp Ridgefield kids rammed a Little Otter boat, knocking a guy's glass eye out. When Mack spies Roger she lays into him - he needs to keep his jet skiers on his side of the lake! Roger quickly moves on, hoping to arrange a date with Mack for later. But Mack thinks it's time to stop screwing. Frustrated, Roger tells Mack she's a faker; she doesn't want to look at her disaster of a life. The only time she's truthful is when she tells Roger she hates him, and now he hates her too.
Mack moves on. The talent show is scheduled to be in three hours, and Cole has discovered the sound system is screwed. When Mack asks whether he thinks she's a faker, Cole asks if this means she was faking during sex with Roger. If Mack's looking for rebound sex, there are better options... Mack admits she wasn't really happy in her marriage; Steve ended it because he didn't want to settle. Now Mack realizes she sees things the way she wants them to be, not the way they really are. Even though it's her favorite thing at camp, Mack tells Cole to cancel the talent show. There's something she has to do.
Marina is just asking Kip not to leave camp when Cole, Buzz, Sarah and Robbie hop into their boat. They're on a mission to swipe Camp Ridgefield's sound system for Little Otter's talent show. As Buzz marvels at Ridgefield's swank buffet (lobster?!), the others load the sound system into a golf cart. Little do they know, Mack is in Roger's office, offering to sell him Camp Little Otter. Just to mix things up, Buzz and Kip decide to steal lobsters and beer causing Ridgefield's CITs to chase them back to the boat. Their narrow escape is one of those summer camp moments that will never be forgotten. Marina puts her head on Kip's shoulder, which is just what he needs to convince him not to leave camp.
When Mack returns to Little Otter, she's stunned to hear the talent show is underway, with Cole acting as master of ceremonies. How did he make it happen? Cole admits the less Mack knows, the better. The next morning, Buzz apologizes to Grace for using the f-word, having decided to turn over a new leaf. When Roger drives up to do a pre-purchase walk-through of the camp, Mack tells him she's not selling, having decided to take out a second mortgage on her house. After signing the papers, Mack tells Buzz he can move into Boys Town; she trusts him. But if he does anything illegal or stupid - she'll kill him.