Warning: The following article contains spoilers for The Last of Us season one finale, “Look for the Light.”
Over its nine-episode run, HBO’s take on The Last of Us (with the help of the original game’s director, Neil Druckmann) has gone to great lengths to expand and add details to the story which it is adapting. This is no different in the season one finale, “Look for the Light.” In one last cold opening, we’re introduced to Anna Williams, who is portrayed by none other than original Ellie herself, Ashley Johnson. This sequence sheds light on how Ellie came to be immune and why her mother is no longer in the picture.
There was a fair bit to glean from this opening before we catch up with Joel and Ellie 20 years later as they approach their final destination, the Firefly-occupied hospital in Salt Lake City, Utah. Let’s break it all down.
How did Anna get bitten?
While Anna is in labor, a pursuing infected bursts into the room and attacks her. While the entire sequence is chaotic, and the assailant is going for Anna’s face for most part, there is a blink-and-you’ll-miss-it moment (seen in the above image) during which she’s bitten on her leg. The injury is revealed in a close-up shot moments later after Anna drives a knife through the infected’s skull.
In the scuffle, Anna barely realizes that she has delivered Ellie and cuts her umbilical cord. When Marlene catches up to her later that evening, Anna insists that she cut the cord before she was bitten, which is a lie; a good few moments had happened between those two events and in the reverse order Anna is telling it.
This is perhaps the very niche and specific circumstance under which Ellie came to be immune with the infection traveling in a small dosage, for just a few moments, through her mother’s umbilical cord. Marlene then goes into a little more detail about the nature of Ellie’s immunity later in the episode while speaking to Joel in the hospital.
Ellie’s immunity, explained
Given Marlene knows some of the truth behind the circumstances surrounding Ellie’s birth, the hypothesis that the Firefly doctors have about Ellie’s immunity is spot on. Ellie has been infected with cordyceps since birth. However, because of the unusual circumstances outlined above, her infection acts differently. Ellie’s cordyceps produces a chemical messenger which makes regular cordyceps think that she is cordyceps, thus any further attack on her system by the fungus will leave her be.
If that strain of cordyceps can be replicated, this means Ellie holds the key to creating a cure for the infection which has gripped the world as the denizens of The Last of Us know it. However, cordyceps live in the brain. In order for a sample of Ellie’s cordyceps to be taken, her brain would need to be dissected, thus ending her life.