It's early when Miguel spies Sarah engaging in her new routine: laps every morning, in addition to peeing in a cup twice a week. Though they haven't seen each other since the great liquor heist, the flirt is on. Kip is disgusted to hear that it's Valentine's Day in July at Camp Little Otter, especially when Marina and hunky Greg show up wearing matching homemade bracelets. When Greg leaves the table, Buzz and Kip gossip that he's a hippy no-talent musician, but Marina knows they're just jealous. Just then, the mean girls pass the table, advising Marina to lay off the bacon. When Kip sticks up for her, Chloe snottily calls him "Emo Boy" before surreptitiously dropping a note at his feet.
Mack is beginning to regret keeping up with the camp's Valentine's Day tradition, but Todd, Raffi and Sheila remind her that it was her mother's favorite event, and the carnival they're putting on that night is for charity. Sheila tells Mack to be grateful she's single and can experience passionate sex again, but Mack insists the only form of love for her is that between mother and son. She hops up on the stage as Robbie cranks a barrel, filled with entries in the "Win a 50 Shades of Little Otter Tour with Mack and Steve" sweepstakes. Robbie pulls out the winning name - it's Roger!
Mack rushes over to Camp Ridgefield to confirm that Roger bought a ticket for the sweeps. He admits to buying 50 tickets, and no, he's not expecting to bone Mack. Later, Kip is accosted by Chloe in the boathouse. After some aggressive lip locking, she wants to know if she's the first girl he's ever kissed. When he insists he got plenty of action in the cancer ward, Chloe takes him at his word, once again loving Kip's "darkness"; it's an aphrodisiac. But no one can know about the two of them! Is that a problem for Kip? Staring a make-out session in the face, Kip could care less. Meanwhile, Buzz has to satisfy his libido with a swimsuit catalog, since pornography is banned at Camp Little Otter. Sadly, Mack walks into the middle of Buzz's session. She's so flustered, she walks into a tent post, and Buzz is mortified.
Robbie has started lifeguard classes, and today he's demonstrating mouth-to-mouth on Sarah. When he asks Marina to select a victim to practice on, she picks Greg, so Zoe calls her a slut. Thinking Marina is moving in on Greg, Zoe decides it's time to get devious. She's going to call a Facebook friend who goes to Marina's high school to get some dirt. Mack's 50 Shades tour with Roger is underway, and Cole doesn't like it one bit; so he decides to chop down a tree in their midst. That's when Buzz runs up to complain to Cole - the whole camp knows his mom caught him having a wank! Dressed as Cupid, Feodor delivers a stack of valentines to Cole, but he's not feeling the holiday this year...
Mack ends the tour in the most romantic spot in the camp, where Steve proposed years ago using a blade of grass as a ring. Back then, Mack thought it was romantic; but now she knows Steve was just lazy, and she's sure she'll never love again. Roger promises love will find Mack again, and the two share a brief moment. Across the camp, Marina exits the shower, only to find that the mean girls have posted copies of her topless Facebook photo all over the camp. Kip runs to her side to help rip down the flyers, but it's too late. Devastated, Marina calls her mom demanding to come home, but it not possible. Marina's mom is at her boyfriend's weightlifting competition in Atlantic City.
That night, the camp's adults gather in the local bar to shoot pool and gossip about Mack's tour with Roger. When Sheila and the guys suggest there's more to Mack and Roger than just good sex, Cole gets quiet. That's when Roger shows up to challenge Cole to a game of pool with a lot of trash talking, suggesting that Cole was dumped from the minor leagues because he didn't want it badly enough. That's when Cole offers to take the discussion outside, asking the rest of the bar if they want to see him kick Roger's ass. When Mack finally gets outside, the fight is already underway. Cole dodges Rodger, who winds up punching a keg and breaking his finger. Mack lays into Cole - isn't he supposed to be setting an example for the camp kids?
At the bar, Robbie recognizes Miguel as the writer Sarah loves so much, so he creates an introduction. Sarah pretends she's never met Miguel before, but the attraction between them is palpable. Back at the camp, Kip lays into Chloe for her part in the Marina debacle. He's done with her. Bumping into Zoe, a furious Marina warns her to watch her back. The next morning, Zoe's screams waken the camp as she discovers a huge chunk of her hair is missing. Over breakfast, Robbie makes fun of Miguel, calling him a pompous douche. On the defense, Sarah calls Robbie a hick snob. She thinks Miguel is interesting and well-traveled. When Robbie fires back, calling Sarah an over-privileged suburban brat, she stalks off.
Marina comes to breakfast hiding in her hoodie. She tells Buzz, Grace, Greg and Kip that she took the topless photo at school last year to give a boy who betrayed her by putting it on the Internet. She just wants people to see her for herself, not her stupid mistake. Zoe enters the dining hall, takes one look at Marina and attacks. Before long, the two girls are in Mack's office. She has the perfect punishment in mind - sorting the camp's garbage. Moments after Mack leaves, the girls start throwing garbage at each other, which ends when Marina catches herself just before cracking Zoe over the head with a bottle. Zoe starts crying: her mother will kill her, because the haircut will take her out of the pageant season. Pretty soon, the two girls realize they have something in common: their mothers are bitches.
Sarah stomps into Mack's office to kvetch about her fight with Robbie. Mack quickly figures out that Sarah is taken with Miguel, and Robbie's threatened. Much as Robbie is the best guy Sarah's ever met, she already knows what their lives will be like, whereas with Miguel... Mack has no advice other than Robbie deserves Sarah's honesty. While building displays for the night's charity carnival, Cole asks Sheila if Mack is still mad at him. Sheila suggests it's time for Cole to tell Mack how he feels about her... which Roger is already doing. He stops by Mack's office with an apology, a bouquet of flowers and an invitation to that night's carnival.
That night, Buzz stops Kip from writing a valentine to Marina - his prose is way too stalker-ish. Kip throws it away, and Greg surreptitiously pulls it out of the trash. Robbie and Sarah are awkwardly spending time together, monitoring the little kids in the bouncy house. They apologize to each other, and Robbie admits he's acting dumb because he thinks Miguel is into Sarah. She explains that she's a little confused, and meeting Miguel has made her more so. After having fun on their date, Mack leads Roger to a remote tent, empty save for a stethoscope. After listening to each other's' escalating heartbeats, they decide it's time to leave the carnival, pronto.
Kip has just given Marina his toned-down valentine, when Greg takes the microphone to ask for everyone's attention, then starts singing a song he claims he just wrote for Marina. The lyrics are from Kip's discarded valentine! Stunned, Marina rewards Greg with a kiss - no one has ever said anything like that to her. Grace finds Buzz alone and moping over his bad day of razzing about the masturbation incident. If he'll go get his special tie and come to the fair, she'll even sing the "Once" duet with him. Buzz runs to his mother's cabin to get a tie, only to interrupt what she's about to do with Roger... and then he walks into a pole on the way out.
The next morning, Kip shoots darts at a heart while asking Cole whether he should fight for Marina or move on. Just then Fyodor runs up dressed as Cupid with one last valentine for Kip. Roger barges into Mack's cottage to finish what they started last night. But hindsight is 20/20, and since Mack knows little about Roger other than her blind lust for him, she wants to put a pin in it - for now. Then she kisses him, in thanks for surprising her. Not conversant in matters of the heart, Roger is thoroughly confused.
After reading his valentine from Chloe ("Fine. I'll be nice to your stupid friend."), Kip tracks her down in the boathouse. Is this Chloe's idea of a romantic apology? Chloe just wants to get back together and make out - and Kip's totally up for that. Mack and Buzz touch base. Between Buzz' hormones and Mack's life as a newly single woman, life is going to get a lot more challenging, so Mack has come up with an unusual Valentine's gift: locks for both of their doors. It's early in the morning when Sarah goes for a swim, which takes her to the dock at Camp Ridgefield. Miguel didn't think he would see Sarah again after he talked about himself so much the other night at the bar. Sarah leaps onto the dock, plants a hot kiss on Miguel, then dives into the lake and swims off.
Camp Little Otter celebrates the spirit of love with a carnival for charity.