Adolescent restlessness has a knack for spawning reckless ideas, and Morty's obsession with school beauty Jessica is no exception. When posters for the school's annual Flu Dance plastered the hallways, Morty felt a mix of anticipation and anxiety—he longed to win Jessica's favor at the event but lacked even the courage to strike up a conversation. The frequent advances of school bully Brad toward Jessica only deepened his self-doubt. Desperate, Morty first turned to his father Jerry for help, only to receive worthless stories of Jerry's own youth. Instead, it was his grandfather Rick, passing by, who cut to the chase with brutal honesty: "Love is just a chemical scam to make species reproduce—your dad's marriage is living proof."
This cynical take didn't douse Morty's hopes; instead, it directed his attention to Rick's laboratory. After relentless pestering, Rick—who always hated trouble but couldn't bring himself to refuse his grandson—finally caved. He plucked a hair from Morty's head and crafted a special love serum using field mouse DNA as the core ingredient. Thanks to the field mouse's monogamous nature, anyone exposed to the serum would develop an unshakable obsession with Morty. "Totally safe, unless she has the flu," Rick tossed off as a casual warning before turning back to his experiments, never imagining this offhand remark would ignite a global catastrophe.
Armed with his "secret weapon," Morty mustered up the courage at the dance to sneak the serum onto Jessica's arm when she wasn't looking. The effect was instantaneous: Jessica, who had previously ignored him entirely, suddenly lit up with infatuation and clung tightly to his arm. This enraged Brad, who stormed over to confront them, but before he could throw a punch, Jessica shoved him away like a protective lioness. Just then, Jessica let out a sneeze—the flu virus had been lurking in her system, and the love serum fused with it in a bizarre chemical reaction. The moment Brad was sprayed with her sneeze droplets, the arrogant bully's expression transformed into one of adoration as he gushed to Morty: "I was so stupid before, Morty—we're meant to be."
Chaos erupted immediately. Brad's sneeze as security dragged him away contaminated the punch bowl at the dance; the ventilation system circulated the virus-laced air throughout the venue, and in the blink of an eye, the pupils of every student and teacher glowed with the same infatuated sheen as Jessica's. When even the principal dropped his dignity and trembled as he confessed his love to Morty, Morty finally realized the situation was spiraling out of control and let out a desperate scream as the crowd closed in on him. Just as he was about to be overwhelmed by the mob, Rick crashed through the dance hall wall in a small spaceship, grabbed Morty, and pulled him aboard. "Told you not to mess with chemical nonsense," Rick complained helplessly as he fired up the ship and made their escape.
To clean up the mess, Rick quickly devised a first "antidote"—a serum made from praying mantis DNA. "Field mice are monogamous, mantises kill their mates—perfect counterbalance," his logic was simple and brutal, but reality dealt him a harsh blow. When the antidote was sprayed over the city via the spaceship's dispersion system, people briefly returned to normal before mutating into half-human, half-mantis creatures—they retained their obsession with Morty but gained the brutal instinct to kill their partners after mating. The city was now a hunting ground, with mutated humans roaring as they chased Morty's trail, and this was only the beginning of the disaster.
Meanwhile, Morty's family was enduring their own nightmare. Rick's earlier joke about "Beth possibly wanting to leave Jerry" had plunged Jerry into irrational panic. When Beth headed to the veterinary clinic for an overnight shift, the paranoid Jerry became convinced his wife was having an affair and drove to the clinic to "catch her in the act." Along the way, the mantis mutation erupted, filling the roads with crazed monsters. Jerry made a surprising discovery: due to their blood relationship, he and his family were immune to the virus. At the clinic, he cast aside his usual cowardice, grabbed medical equipment to fend off the mutated creatures attacking Beth, and the couple drove through the chaotic streets to find their daughter Summer hiding in the basement of their home. A family once torn apart by conflict unexpectedly found reconciliation amid the apocalyptic crisis.
High above, Rick was making one last desperate attempt. He mixed DNA from koalas, rattlesnakes, dinosaurs, and various other creatures to create an "all-purpose restoration serum." However, this seemingly perfect formula completely shattered the balance of biological genetics—instead of reverting to human form, the mutated humans merged into grotesque, flesh-blob monsters known as Cronenbergs. Standing on the spaceship's gangway, Morty stared down at the hellish city below and finally snapped at Rick: "You ruined everything!" For once, Rick didn't retort; he simply worked silently at the control panel. "There's one last way, though it's a bit cruel."
The other side of the portal revealed a parallel universe nearly identical to their own. The crisis here had already been resolved by another "Rick," and humanity had returned to normal life. Unfortunately, the Rick and Morty of this universe had been killed in a lab accident, their bodies lying in the backyard of their home. "Welcome to your new home," Rick said, handing Morty a shovel. Under the moonlight, the two teenagers buried "the other versions of themselves"—the dirt covering not just the corpses, but all the ties that bound them to their original world.
As a new day dawned, Jerry, Beth, and Summer prepared breakfast as usual, unaware that the Rick and Morty standing before them were not the ones they'd known. Morty looked at his familiar family, his heart filled with complex emotions; Rick, meanwhile, casually opened the refrigerator to grab a beer, as if the previous night's world destruction and dimensional travel had been nothing more than a routine adventure. In their original universe, amid the ruins overrun by Cronenberg monsters, Jerry clutched a shotgun to protect his family—they would never know that the loved ones (or nuisances) they cared about had begun a new l