This post contains spoilers for the “Walking Dead” franchise.

Robert Kirkman and Tony Moore’s “The Walking Dead” comic book series begins in the heart of chaos. Rick Grimes, a deputy shot in the line of duty, wakes up from a coma and finds himself in the middle of a zombie apocalypse. This shock of witnessing the world on the brink of collapse is superseded by the urge to survive, which leads Rick to a group of survivors. One would think that reuniting with one’s family would be a happy occasion, but a nation overrun with zombies proves to be the cause of unimaginable grief and heartbreak. Indeed, after Rick reunites with his wife and son, a series of everyday obstacles and moral dilemmas await him, forever changing the man he used to be when he woke up from his coma.

Kirkman, however, does not tell us how the zombie apocalypse came to be. There are chunks of lore, speculation, and working theories fleshed out from time to time, but the focus is exclusively on the aftermath of such a terrible catastrophe. How do people cope when their loved ones transform right in front of them? And how do they let go of grief while searching for reasons to live and love again? These questions haunt AMC’s “The Walking Dead,” as the series gets the opportunity to dive deeper into what makes Rick Grimes tick, along with the many survivors he encounters over the years. That said, the TV show always evaded the mystery surrounding the outbreak’s origin, which, to be frank, doesn’t negatively impact the story. After all, “The Walking Dead” has always been about evolving morality and its consequences.

Fast-forward to 2020’s “The Walking Dead: World Beyond.” The spin-off series not only centers on a brand-new group of young survivors, but it also solves this 10-year-old mystery when we least expect it. In point of fact, the second season’s post-credits scene features a zombie outbreak origin story that is worth dissecting. Without further ado, let’s take a closer look.

In “The Walking Dead: World Beyond,” we learn that a biomedical facility in France was the source of the franchise’s worldwide zombie outbreak. It is insinuated that something really bad happened here, which the researchers were unable to prevent or contain. However, a scientist is seen returning to the abandoned facility, believing that clues for a cure lie here. She runs into a survivor, to whom she declares her intentions to end the zombie apocalypse gripping the world at large. “End this? You started this,” the survivor replies, before viciously killing her and mutating into a faster, more aggressive zombie. The France origin story is also confirmed in “The Walking Dead: Daryl Dixon,” where we get glimpses of the earliest days of the outbreak and learn that some scientific experiments made the situation worse by inadvertently creating synthetic and acidic zombie variants.

So, we know where the outbreak started, but what do we know about the strain of viral disease responsible for the situation? Thankfully, “The Walking Dead” and its spin-offs do explain this aspect in great detail. Wildfire is the viral disease responsible for resurrecting infected hosts, which corrupts a living brain enough to alter the host’s evolutionary functions. These infected hosts — zombies, if you will — attack other living organisms on instinct and seek to spread a secondary infection. To make matters worse, initial bouts of Wildfire are asymptomatic, meaning that there’s no surefire way to determine whether someone is infected if they choose to conceal it. Symptoms surrounding a secondary infection include delirium, chills, nausea, and eventually, complete organ failure when host bodies become zombified.

This unprecedented chain of infections eventually led to total societal collapse. Fringe groups of survivors are seen doing their best to keep the spirit of the human race alive, but the overlapping notions of human greed, conflict, resilience, and natural selection paint a hopeful but extremely dire picture.

While these lore drops are serviceable, what did Kirkman have to say about the origin story? After all, the original “Walking Dead” comics and TV show deliberately avoided revealing how the infection began, as their creatives felt that it would demystify an integral aspect of the franchise. Kirkman also teased different origin stories in now-deleted social posts, including one that involved alien space spores (via Forbes), but none of these statements have been established as canon. For now, we will have to stick with the France biomedical facility outbreak fiasco as the canon outbreak origin, given how it links disparate character perspectives and maps an outline of how humanity is now on the verge of extinction.

The only thing that this origin tale helps establish is a coherent timeline, with Day 1 marking the outbreak at the facility and Day 628 marking the end of the Negan war, with Rick’s post-coma journey starting on Day 59. This is just the narrow scope of events that span the “Walking Dead” franchise, and once we account for the connected spin-off arcs, things start getting confusing.

Moreover, if we re-examine every arc that makes “The Walking Dead” a compelling survival horror story through the lens of the France origin tale, nothing actually hampers or alters our understanding of the property. This is because the stakes always lie in interpersonal dynamics that constantly keep changing in a post-apocalyptic world, along with the prospect of love or betrayal blooming in the unlikeliest of places. Sometimes, the emotions evoked are not as drastic or intense, as the quiet, tender empathy shared between two strangers conveys much more than any overblown zombie-killing sequence. That said, dramatic, exaggerated action lies at the core of the franchise, constantly pushing our perception of how the average person is forced to become a hardened survivor. The alternative, after all, is to succumb to Wildfire and lose one’s sense of self forever.