As the sun sets over the sparkling lights of Wonder Wharf, an unsettling atmosphere envelops the vibrant carnival. In the shadows of the attractions, a tense struggle brews, leading to a shocking eruption of gunfire and the heavy sound of a body crashing to the ground. With anticipation hanging thick in the air, we shift to Bob's Burgers, where the Belcher family prepares for another hectic day in their beloved restaurant.
Fast forward six years since that fateful night, and the remnants of the past still linger, haunting the restaurant. Bob (H. Jon Benjamin) and his wife Linda (John Roberts) are gearing up for a critical meeting with their bank loan officer, while their children Tina (Dan Mintz), Gene (Eugene Mirman), and Louise (Kristen Schaal) eagerly count down the days until summer break. For Bob, this means prepping for the Wharf's anniversary celebrations, while his kids have ambitious plans — from Tina's long-standing crush on Jimmy Jr (also H. Jon Benjamin) to Gene gearing up for a performance with his musical group, the Itty Bitty Ditty Committee.
Despite their seemingly joyful daily life, tensions bubble beneath the surface. Louise yearns to shake off her "baby" image, especially after a humiliating encounter with classmate Chloe Barbash (Stephanie Beatriz), who mocked her cherished pink bunny ears. Meanwhile, Tina's daydreams of horse riding with Jimmy Jr capture her mind, leaving her anxious that the harsh truths of love might crush her idealized fantasies.
In the midst of navigating business setbacks, including a cold reception from the bank and a less-than-stellar burger presentation, disaster strikes. A sudden sinkhole erupts in front of the restaurant, sealing off access and shrouding the Belchers in confusion. Enter Calvin Fischoeder (Kevin Kline), their quirky landlord, along with his brother Felix (Zach Galifianakis) and cousin/lawyer Grover (David Wain). Calvin’s arrival offers a sliver of hope — a temporary halt on rent payments while the restaurant recovers. But as the day progresses, it swiftly becomes evident that their troubles are far from over.
As the hours roll on, Bob's frustrations with the dwindling customer base boil over. Meanwhile, Louise recognizes a chance to redefine her image, persuading Tina and Gene to participate in a wild plan: creating a video of her attempting to climb the sinkhole. Her venture ends comically when she tumbles into the hole and unearths a shocking secret — a skeleton, long forgotten, lies in wait beneath the surface. This discovery belongs to Cotton Candy Dan, the poor soul whose demise ignited a series of unpredictable events. The Belchers, initially hoping this grim find would clarify matters, are instead dragged deeper into chaos as Calvin is arrested, charged with Dan’s murder — an accusation he vehemently contests.
Determined to navigate this turmoil, Louise ironically flaunts one of the skeleton’s teeth at school, much to Chloe’s malicious excitement. Their friend Teddy (Larry Murphy) steps in to assist Bob and Linda in revamping their business strategy, crafting an impromptu burger cart that they must operate covertly to evade legal trouble.
In the meantime, Louise convinces her siblings to skip school, embarking on a quest to clear Calvin’s name. Their investigation takes them to the heart of the carnival, where they encounter a shadowy group known as Carnietopia. The trio soon butts heads with Mickey, a petty criminal entwined with the carny world. Unfortunately, their inquiries meet only resistance and evasions, leading them to infer that Dan’s old associates may be hiding the truth.
As the search deepens, Louise, Tina, and Gene stumble upon a crucial clue: Cotton Candy Dan was last seen in the company of Felix. Determined, the kids trail Felix to his lavish treehouse, where they overhear his conversation with his ex-wife. It's apparent that Felix is planning to flee the country, adding complexity to their quest for clarification regarding Dan’s shocking death and the framing of Calvin.
While Bob, Linda, and Teddy continue to tackle their restaurant hurdles, they inadvertently discover a sacred shrine for Cotton Candy Dan, setting off a whirlwind of events testing their resolve. Their accidental disruption of the shrine leads to a harrowing chase from a furious group of carnies, while Bob's panic about their business becomes increasingly palpable. Linda’s support tries to lift his spirits, although it’s evident their situation is precarious.
Concurrently, the kids — Gene, Louise, and others — come across the Mole Hill ride, discovering a clandestine hideout amidst its maze-like structure. Here, they reunite with Calvin and Felix, who are in hiding since Calvin's recent release due to insufficient evidence. Before long, the kids find themselves face to face with Grover, who has returned to settle old scores.
Amid rising tensions, Louise notices a photograph featuring the Fischoeder brothers and a familiar face — Grover, wearing a cufflink that closely resembles one they found in Felix's treehouse. This realization is compounded by a bite mark on Grover that matches the teeth of the skeleton they uncovered earlier, leading to the shocking conclusion: Grover is behind Dan’s murder.
As the true story unfolds, Grover, cornered, resorts to holding the group at gunpoint. Meanwhile, Bob and Linda remain oblivious to the turmoil unfolding, comically tumbling into danger themselves.
Grover divulges his twisted motivations, revealing his earlier ambition to construct a theme park over Wonder Wharf, thwarted by Dan’s fatal accident. He admits to accidentally killing Dan and hiding the body, hoping the chaos would allow him to pursue his dreams unimpeded. Unbeknownst to him, a construction worker has layered Dan's remains in dirt, now the very spot outside Bob's restaurant.
As Grover’s malevolent intent to frame Calvin and Felix comes to light, the Belchers scramble for their lives in a go-kart, trying to escape his onslaught. Unfortunately, his bulldozer traps them in a precarious pit, leading to desperate moments where Louise's self-accusations spiral. Gripped by despair, she feels responsible for the turmoil ignited by her need to prove her bravery.
Yet, just when it seems all hope is lost, Bob and Linda's words of comfort cut through Louise's anguish. They share the beautiful backstory behind her cherished bunny ears, weaving a heartfelt connection through generations. Just then, Bob taps into his hidden strength, giving their go-kart one last charge, leading them bursting back to the surface, met with Teddy’s relieved expression.
Once the dust settles, the Belchers recount their harrowing adventures to the police. Bob and Louise unite to extinguish the lit fuse threatening the Wharf, ultimately liberating Calvin and Felix. With Sgt. Bosco (Gary Cole) and his team capturing Grover, his schemes draw to a close.
In the aftermath of the turmoil, the Belchers come together to fill in the sinkhole, restoring business and life at Bob's Burgers. As a token of appreciation, Calvin grants them a month’s free rent. Tina boldly confesses her feelings to Jimmy Jr, sealing it with a sweet kiss. Louise sheds her inhibitions, discarding her iconic hat during a school performance, symbolizing her newfound freedom.
As Gene performs once more, the audience may be smaller than hoped, yet the unity of the Belcher family shines through. They reopen their restaurant, emerging stronger together than ever before. As the credits roll, viewers are treated to a whimsical vision of Tina's imagination that depicts her riding horses with Jimmy Jr amidst a fantastical backdrop of zombies — a delightful reminder of endless possibilities.
