The following contains spoilers from The Last of Us Season 1, Episode 1, "When You're Lost in the Darkness," which debuted Sunday, Jan. 15 on HBO.

Fans of Naughty Dog's The Last of Us game series knew going into the HBO adaptation that changes would be made. While most of the TV show's first episode is recognizable to those who played the games, there are also some immediate differences. The storytellers made an intriguing decision with their timeline that, unfortunately, means fans are unlikely to see Joel sing Pearl Jam's "Future Days" to Ellie.

The Last of Us opens with Joel during the outbreak of the mutated Cordyceps fungus. Yet the circumstances are slightly different, because rather than 2013, the outbreak happens in 2003. Showrunner Craig Mazin may have made this change to set the outbreak closer to September 11, 2001. The September 11 terrorist attacks and the United States' response to them seem like the allegory the show's creative team is leaning into. And in the grand scheme of things, it's just a minor change affecting things like technology available and pop culture. Except, "Future Days" is a bit of pop culture Pearl Jam didn't get around to creating until 2013.

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Why Joel Singing 'Future Days' to Ellie Is Important to The Last of Us

This particular problem is one far in the future -- into Season 2 or even later depending on the pace of storytelling. The moment in question comes early into The Last of Us Part II, which mostly takes place four years after the events of the first game. In a flashback-style scene, players watch Joel give Ellie her guitar. By way of showing her how to use it, he plays and sings the opening of "Future Days" from Pearl Jam's 2013 album Lightning Bolt. He then grows self-conscious and stops.

It's not a spoiler to say that tension between Joel and Ellie is an important element of The Last of Us' story and their relationship. However, the moment when Joel sings to her is one of the most heartwarming in the entire game. It's a rare scene that would play out exactly as it does even if the setting was not a civilization devastated by the zombie apocalypse. However, the different start date of said apocalypse means that Pearl Jam never got around to releasing Lightning Bolt. And the themes of grief and loss in "Future Days" were remarkably apt for The Last of Us.

Of course, the song is the only thing that would have to change if The Last of Us on HBO wants to include the scene anyway. There are plenty of songs recorded before 2003 that could work in such a moment. Yet there's also a way the show could keep the scene as is and it's great news for (the fictional) Pearl Jam.

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Would Pearl Jam Appear on The Last of Us and Sing It First?

Tess and Ellie in The Last of Us

Unlike The Walking Dead, which just finished on AMC, The Last of Us has "hope" baked into its narrative from the beginning. Ellie is the simple solution most stories in the zombie genre lack. So rather than a very violent and heartbreaking slog across the country, perhaps Joel and Ellie encounter equally new-to-the-story settlements of people. If new Marvel Cinematic Universe star Bill Murray could make it in Zombieland, why can't Pearl Jam avoid the clickers and other beasties in The Last of Us? The beauty of "Future Days" is that it is a song that could believably be written after the fall of civilization.

What if Joel and Ellie happen on a settlement where Pearl Jam just happens to be and they hear the song? When he later gives the guitar to her, him playing the song would have even more impact. Rather than just a pop song from before the end of the world, it becomes a song that has a personal meaning to both Ellie and Joel. That kind of natural synergy is more than enough to buttress the suspension of disbelief when a famous grunge rock band shows up in the zombie wasteland. It also makes the scene more than just a cool Easter egg for fans of the games. Also, Pearl Jam often gets its songs in TV series, but rarely appear themselves.

Whatever decision Mazin and company make about Pearl Jam, it will surely not be one made lightly. Despite the minor differences in the game's story, The Last of Us is a faithful adaptation of the elements that captivated players and set up emotional payoffs video games rarely deliver. The "Future Days" moment is one of the and the producers of the HBO series would be foolish not to honor it.

The Last of Us debuts new episodes Sundays at 9:00 pm. on HBO and HBO Max.