The Big Clue Everyone Missed Early On In All Of Us Are Dead Season 1

The Korean zombie thriller "All Of Us Are Dead" became Netflix's fifth most-watched non-English series debut in the streaming juggernaut's history, and for very good reasons. Part zombie apocalypse survivor story and part coming-of-age romantic drama, the first season of "All Of Us Are Dead" provided 12 jam-packed hours of entertainment that has kept the show on the most-watched lists across the globe since its release on January 28, 2022. Following a group of students trapped in their high school during a zombie virus outbreak, the students find themselves at ground zero, abandoned by the government, and left to survive with their own skills and resources. High school is hard enough without watching your friends transform into flesh-hungry monsters, or worse, having to kill those same friends in order to survive.

The Jonas virus, created by brilliant scientist turned school teacher Lee Byeong-chan and named after philosopher Hans Jonas, was originally concocted as a way to provide Mr. Lee's bullied son Jin-sun a medical way to transform fear into rage and aggression and motivate him to fight back against those who cause him harm. Unfortunately, the virus mutated into mindlessness and bloodlust, kickstarting the events that would lead to a zombie outbreak. Everyone is susceptible to the Jonas virus, either becoming a zombie or asymptomatic "hambies" (half-human, half-zombies). That is, everyone except Nam On-jo (Park Ji-hoo).

Most of those infected with the Jonas virus turn into out-of-control zombies operating purely out of rage and destruction, but those who turn into hambies can teach themselves to control their zombie urges, and pass themselves off as human. It's a rare result of the virus, but it is possible. After Kim Hyeon-ju (Jung Yi-seo) is bitten by an infected hamster, locked up for days, and eventually taken to the school infirmary, she starts lashing out, spreading the Jonas virus, and infecting the students, teachers, and nurses trying to help her. It was assumed that Nam On-jo was bitten during the outbreak, as we later see her father asking her if she is okay while she holds her bandaged wrist.

Nam On-jo doesn't show any signs of zombie infection, sensitivity to 24hz frequency tones, or any other guaranteed signs of being either a hambie or a full zombie. Since On-jo is scratched before chaos breaks loose and her bandaged wrist is hidden under the sweater, no one checks to make sure she isn't infected. This all takes place right before the outbreak explodes into a full-on epidemic, so there were clearly bigger fish to fry than questioning On-jo's asymptomatic wound while the entire school watched their classmates transform into bloodthirsty rage monsters.

Those who become hambies have been shown to have regenerative abilities, with students Yoon Gwi-nam and Choi Nam-ra suffering devastating injuries that they're able to gradually recover from. This has led many to believe that Nam On-jo was likely able to heal her own wounds. It's a great theory, but if viewers go back and rewatch the moment Kim Hyeon-ju finally goes full zombie and attacks everyone around her, she snaps at Nam On-jo, but doesn't actually bite her. Professor Park Sun-hwa sees Hyeon-ju snap at On-jo, and asks if she's okay, but she just nods while holding her wrist. Moments after her paramedic father bandages the wound, Lee Cheong-san asks On-jo if she was bitten, and she replies that it's only a scratch.

If On-jo only sustained a scratch, there was no passing of blood between the two women. The school nurse, however, was actually bitten by Hyeon-ju and became the first zombie to spark the domino effect of infection throughout the rest of Hyosan High. That said, at the end of the first episode, a zombie charges at On-jo only to scream in her face, but not before sniffing her. The zombies don't attack one another, so did this zombie sense what no one else knew? 

While it seems like the scratch theory is the strongest, all of this could change in future seasons of "All Of Us Are Dead." We already know that the Jonas virus is capable of mutating and turning into different variants depending on the host's biochemistry. There's always a chance that On-jo could wind up as some sort of "super hambie" in the next season and lead to even more zombie carnage. At this point, it's hard to tell just what the Jonas virus is capable of. But If On-jo has been an asymptomatic host this entire time, she could also very well be the source of a cure.