The movie kicks off with Ron, portrayed by Blake Anderson, the janitor, jamming to "Black Widow" as he roams the halls of a research facility. While diligently cleaning, he stumbles upon Dr. Pieter Morris, played by Theo Kypri, who leaves for a snack at the vending machine. Curiosity takes hold of Ron as he notices something unusual behind a curtain. To his horror, he discovers a man hooked up to a machine, his skin strikingly pale and veiny. As Ron grasps his wrist, the man twitches, sending Ron reeling back and causing chaos with the machine. In a frantic attempt to help, he tries CPR until he realizes with shock that his hands plunge through the man's stomach. The shocking moment escalates as the man suddenly revives, launching himself at Ron, just as Pieter struggles with a bag of chips.
The scene shifts to three childhood friends, Ben (played by Tye Sheridan), Carter (played by Logan Miller), and Augie (portrayed by Joey Morgan), who are with their Scout Leader Rogers, depicted by David Koechner, on the day of their scouts registration. Sadly, the turnout is dismal with only one kid present, who quickly leaves after watching a cringeworthy video. Despite feeling demoralized, Rogers reminds the boys that tonight marks a significant event for Augie as he is set to earn his Condor Badge.
During the drive home, Carter expresses to Ben the need to break the news to Augie about their desire to quit scouting, a decision that weighs heavily on them after the loss of Augie’s father. While debating their future, a deer unexpectedly runs into their path, resulting in a flat tire. As they attempt to fix it, Carter’s sister Kendall, portrayed by Halston Sage, arrives with her boyfriend Jeff and friend Chloe. Ben harbors a crush on Kendall, while the boys find themselves distracted by the possibility of attending a secret senior party that evening. Later, Ben and Carter run into their grumpy neighbor, Ms. Fielder, played by Cloris Leachman, who reminds them to keep their garbage off her property.
In a nearby wooded area, Rogers discovers Pieter's badge while a lurking threat stirs in the bushes. The deer, now transformed into a terrifying zombie, attacks him, and in a shocking twist, he becomes the next victim of the zombie outbreak. Meanwhile, on their way to the ceremony, Ben and Carter make a stop at a liquor store, where their plan to acquire beer backfires dramatically when they attract unwanted attention from a drunken bum. This bum eventually leads them to Denise, played by Sarah Dumont, who impressively snags the beers for them.
As the boys join Augie in the woods, they spend a nostalgic day filled with antics until darkness envelops the campsite. However, after Augie nods off, Ben and Carter’s plans to sneak out to the party take a hit when Augie discovers their intentions. Heartbroken yet understanding, he encourages them to go.
A series of misadventures ensue as Ben and Carter find themselves drawn into a horrifying zombie apocalypse. They discover the liquor store is in ruins, the bouncer at the strip joint has morphed into a zombie, and they must flee while encountering grotesque creatures along the way. The chaos escalates when they’re cornered by hordes of undead, forcing them to rely on each other as they strategize to rescue their friends amidst the madness.
They later realize the party is at a rec center, and while fighting for their lives, the boys encounter the undead, including Kendall’s ex-boyfriend, Jeff, who finds himself amidst the chaos as zombies close in. With some improvised weapons and teamwork, they push through the horde, leading to hilarious and heartwarming moments as they band together to save the day.
Ultimately, through thrilling action and comedic relief, Ben gathers the courage to pursue Kendall, and with a touch of charm, seals their moment with a kiss that promises adventure beyond the chaos they faced.
As the credits roll, we are treated to glimpses of their newfound connections, illustrating how friendships can withstand even the direst circumstances. The final scene offers a hilarious twist, leaving audiences questioning what truly lies beyond a zombie apocalypse.
