Why is Ellie immune in The Last of Us? The show dives into greater detail

Spoiler Alert! This article provides plot details for the season finale of The last of us.

Joel and Ellie have reached the end of their journey in Season 1 of The last of us. Adapting the critically acclaimed PlayStation video game of the same name, the hit HBO show follows the survivors of a monster Cordyceps fungal infection that has decimated the United States.

Twenty years after the initial outbreak, Joel Miller (Pedro Pascal) is a smuggler in the quarantine zone, deeply traumatized by the death of his daughter within hours of the virus spreading. He is accused of escorting a teenage girl named Ellie (Bella Ramsey) across the country in hopes her immunity to the virus could help save the world once and for all.

But why is Ellie immune to it? Cordyceps first of all? The show goes into more explicit detail than the game.

Typically when someone is bitten by an infected person The last of us, The Cordyceps takes over her body within days, effectively turning the victim into a monster. Miraculously, that’s not the case with Ellie. Although she was bitten on her right arm, the infection does not affect her body. For this reason, Marlene (Merle Dandridge), the leader of the Fireflies rebels, hires Joel to find a doctor with Ellie who can test her immunity.

Interestingly, the show explicitly discusses where her immunity came from. The opening moments of Season 1 Episode 9 – “Look for the Light” – is a flashback showing Ellie’s mother Anna (played by Ashley Johnsonwho portrayed Ellie in the original games). Anna, still pregnant with Ellie, runs off a walker on her way to a hangout to meet up with her fellow Firefly rebels, including Marlene.

She is the first to arrive and tries to block the doors inside the house to keep the infected out while her waters rupture. Unfortunately, a walker breaks through their barricades just as Anna prepares to thrust. After a brief struggle, she manages to kill the walker and gives birth to Ellie just seconds later. However, Anna discovers that she was bitten on her right thigh before she can cut the umbilical cord. Despite this, she cuts it off and holds Ellie for as long as she can.

Marlene arrives some time later, and Anna lies and tells her that she cut the umbilical cord after she was bitten. She tells Marlene to kill her before she turns around and take care of Ellie in her absence.

In all likelihood, Ellie accidentally conceived them Cordyceps Immunity after her mother was infected. She received a dose of the virus through Anna’s amniotic fluid, where it developed in her body.

According to Marlene, her Firefly doctors theorize that because the Cordyceps who have been with her since birth, the virus is sending out a chemical message in her system. This message supposedly communicates with foreign countries cordyceps, make the virus believe that Ellie herself is already infected. Given enough time and research, Ellie’s immunity could even be turned into a cure.

People who played the original game may have already gotten this hint. During the segment where you play as Ellie in Winter, players will have an opportunity to search her backpack and find one farewell letter from Ellie’s mother. The letter itself implies that she was infected before birth, which would explain her immunity.

However, the show takes it a step further by revealing exactly what caused Ellie’s unique condition.

Season 1 of The last of us now streams in full on HBO Max.