Who are the Fireflies in The Last of Us? Episode 1 explained

As briefly detailed in an interview right at the beginning of the episode, the cordyceps fungi infects creatures and controls their brain, using them to continue the fungi. It's adapted from a version that controlled insects because climate change forced the fungi to adapt.

If you want more information on cordyceps and the creatures it creates, we've written a guide to The Last of Us zombies where we answer all your questions here.

The cordyceps fungi enters the world of our characters when the grandma, who lives next door to Sarah, starts chomping on her family members one night. Sarah stumbles in and her zombie apocalypse begins.

But how does this old lady get the cordyceps, given that no-one around her does? Well, that's actually explained during Sarah's subsequent car ride with Tommy and Joel — but given that it's a tense scene, with lots to see during the journey, you'd be forgiven if you hadn't been paying attention to the dialogue.

Turns out, the cordyceps spread most effectively in the inner cities, far from where Joel and Sarah and their neighbours live. But it's explained that the old lady was frequently taken into the city for doctors to check up on her, so she likely caught it then.

When Sarah visits the family earlier in the day, the old lady is acting strangely, which was clearly the cordyceps taking hold.

During the first half of episode 1, we follow Sarah over the course of her day, and lots of her efforts involve her trying to get a watch fixed. She does so because it's Joel's birthday and she's getting the watch fixed as a present for him (with his own money, admittedly).

The significance of this watch isn't explained — we're not told where Joel got this watch or why it's broken.

When Sarah mentions that Joel has been reluctant to get it fixed himself, he seems wounded, so it implies there's some tragic backstory there. The lack of Sarah's mother is also interesting; perhaps the watch was hers.

Later in the episode, Ellie points out the watch suggesting it's something that the show wants us to keep in mind — maybe we'll find out more about the backstory later. But for now, don't worry, you didn't miss anything.

The first episode of The Last of Us takes place in two distinctive locations and time periods. You'd be forgiven for forgetting where, since the titles only pop up briefly.

In 2003, Joel and Sarah are living in Austin, Texas, when the cordyceps outbreak begins. When we jump forward 20 years, Joel is now living in Boston, nearly 2,000 miles away. We're never told why he's relocated.

When the events jump forward 20 years to the year 2023, we begin by following a young child wandering around the outskirts of Boston, eventually being discovered by some FEDRA workers (more on them later). After being asked some questions, she disappears from the story... at least, it would seem.

The child doesn't disappear from The Last of Us though, as the eagle-eyed may spot her fate quite soon afterward in the episode.

When we meet Joel, he's working a detail burning the bodies of the infected, carrying them from a truck to a bonfire. One of these bodies has a bag on its head, however, the top, trousers and shoes (notably the bright green laces) are the same as those of the child from before.

One more detail: through the episode, we see FEDRA using tests to see if someone is infected, and the machine they use returns a green light if the person is safe or a red one if they're infected. In the child's interview, we see a red light — however, you'd be forgiven not for understanding the significance of this, since it's the first occurrence of such a test being used in the episode.

It's implied, then, that the child dies after this interview, likely at the hands of FEDRA. It's quite a dark detail that you could have missed.

While Joel's brother Tommy features prominently in the prologue section of episode 1, he's vanished by the time skip later in the episode. But his fate is mentioned in the odd line here and there.

At some point in the last 20 years, Tommy clearly linked up with the Fireflies, a rebel faction that we'll explore later on in this article. He must have left Joel at some point.

Joel and Tommy stayed in contact via radio towers, with Tommy generally responding within a day. But now Joel says that he hasn't heard from Tommy in three weeks. Joel is now trying to find a car battery so he can drive out west to Wyoming to search for his missing brother. 

So Tommy's fate is uncertain, though it'll very likely get explored in future episodes.

The leader of the Fireflies in Boston, called Marlene, clearly has a history with Ellie.

Marlene admits she put Ellie in military school when Ellie was younger, though we're never told why or what caused Ellie to be put in the care of Marlene before that.

Marlene also knows a secret about Ellie, which is likely about her resistance to cordyceps (revealed later in the same episode).

When Marlene and Ellie are talking, Marlene mentions a character called Riley, and this name clearly shocks Ellie.

But who is Riley? While this character is never mentioned in the rest of the episode, fans of the game will recognize it, as this is a main character in an expansion pack to the game of The Last of Us.

This expansion is being adapted into the first season alongside the main game, so we'll likely find out more about Riley in future episodes. But we won't say any more, as that'd be a dirty old spoiler. Just be safe in the knowledge that you didn't miss anything.

When Joel is in Boston, it's being run by a paramilitary force, who are clearly well armed and enforce a 12-hour curfew each day.

But who is this? Well, it's a government agency known as FEDRA — this stands for Federal Disaster Response Agency, and it's in charge of ruling the quarantine zones of the United States.

It exists alongside the Department of Defense and Center for Disease Control in being one of the main remaining aspects of the US Government, and in the games it incorporates the US military too. 

While FEDRA can't quite be classified as the "bad guys," as they're certainly looking after the survivors of the cordyceps plague, they're shown to rule with an iron fist, and they're antagonistic to Joel, Tess and Ellie as they try to sneak out of the quarantine. 

The Fireflies are a rebel militia faction who aren't too keen on the military oppression taking place in the quarantine zones.

In episode 1, we hear about lots of terror attacks committed by the Fireflies, including a car bombing and a rooftop shooter, though it's stated that this faction is losing ground and support in its guerilla war.

We meet the character Marlene, who is the leader of the Fireflies in the Boston Quarantine Zone, and who gives Joel and Tess their quest at the end of the episode to transport Ellie in exchange for a car. Suffice to say, we'll be seeing more of them as the story goes on.

A surprise twist at the end of episode 1 is the fact that Ellie has been infected with cordyceps. We find this out first when a soldier tests Ellie, which Tess notices and freaks out over.

Given that we see posters earlier in the episode that confirm it takes only hours to be infected if you're bitten on your arm, you'd imagine that this would make The Last of Us a race against time, but that's not the case.

Ellie states that she got the bite weeks ago, and it certainly looks more healed than it would if it were only a few hours old. So what's happening here?

Well, that's certainly something we'll explore later in the series.

At the end of the episode, we see the radio turn on in Joel's apartment. It plays the Depeche Mode song "Never Let Me Down."

This is relevant because earlier in the episode, Ellie discovers Joel's smuggling radio code — when a song is played on the radio, the decade it's from indicates different meanings, and the '80s means "trouble."

So the real question is when is "Never Let Me Down" from? The answer to that is 1987, so whoever Joel is in communication with is in trouble.