In the Last of Us Season 1 finale, Joel (Pedro Pascal) and Ellie (Bella Ramsey) finally meet back up with the Fireflies. Things take a dark turn, however, when Marlene (Merle Dandridge) tells Joel that the Fireflies’ doctor plans on removing the Cordyceps infection directly from Ellie’s brain to produce a cure for everyone else. Joel predictably doesn’t take the news that Ellie will die as a result of the surgery well.
Both he and Ellie seemed to believe throughout The Last of Us Season 1 that the Fireflies would just need to run some tests on her and take some of her blood in order to make their world-saving cure. When Joel learns otherwise, he’s not only shocked but forced to make a choice between saving humanity and saving Ellie. For Joel, that decision doesn’t require much deliberation.
What most first-time viewers might not have realized, though, is that The Last of Us actually set up its final Ellie twist several episodes prior to its finale.
In The Last of Us Episode 5, Sam (Keivonn Woodard) reveals to Ellie that he was bitten during the episode’s climactic Infected attack. Ellie, in response, cuts her palm and smears some of her blood on Sam’s wound in the hopes that her immunity will be able to stop Sam’s infected transformation. Her attempt, unfortunately, doesn’t work.
The scene not only highlights the childlike naivety that Ellie essentially loses over the course of The Last of Us Season 1, but it also signals to viewers that giving Ellie’s blood to someone else isn’t enough to make them immune like her. Thanks to the Last of Us Season 1 finale, viewers now know that’s because it isn’t Ellie’s blood that’s immune to the show’s central Cordyceps infection.
Instead, it’s the Cordyceps that have been growing with Ellie ever since she was born and, in specific, the “chemical messengers” that Ellie’s version of the infection send to any foreign Cordyceps that her body comes into contact with. Those messengers are, apparently, only present in Ellie’s brain, which is why the Fireflies want to remove portions of it in The Last of Us Episode 9.
Ellie’s final conversation with Sam is one of the saddest scenes in The Last of Us Season 1 — if not the saddest. The scene’s tragedy isn’t just the result of what ultimately happens to Sam and Henry, either. It also stems, in no small part, from how innocently both Sam and Ellie try to confront and deal with the weight of what lies ahead for them and their friendship. Rather than truly addressing the inevitability of Sam’s transformation, Ellie chooses to believe that she can beat it.
Her failure to do so only makes Sam and Henry’s deaths that much more tragic. Whether she realized it or not, her final moments with Sam also revealed the truth about Ellie’s immunity and, even more importantly, what she’d need to give in order to share it with everyone else.
The Inverse Analysis — Ellie and Sam’s final conversation in The Last of Us Episode 5 plays out very differently from how it does in the original Last of Us game. In the latter version, Ellie doesn’t find out that Sam was bitten until he’s already begun to turn into one of the Infected. Like most of the changes that HBO’s The Last of Us makes to its source material, though, the show’s version of Ellie and Sam’s final conversation not only makes their story all the more tragic, but it also carries even more weight than either realize.
In this case, the ineffectiveness of her blood should have been all that Ellie (and those watching at home) needed to know to deduce that manufacturing a cure wasn’t going to be nearly as easy as she, Joel, and everyone else hoped.
The Last of Us Season 1 is streaming now on HBO Max.