In the latest episode of HBO’s The Last of Us, the series took its biggest swing away from existing video game canon yet and, in the process, gave viewers the show’s best character development so far. The episode also saw Ellie (Bella Ramsey) and Joel (Pedro Pascal) finally hit the road for what is sure to be an interesting road trip.

Warning: The following contains spoilers for the third episode of HBO’s The Last of Us. If you haven’t watched yet, head over to HBO Max to stream the episode now.

In the episode, we learn more about Bill and Frank, the men that Tess (Anna Torv) advised Joel take Ellie to. What we see, though, is their love story–and it’s quite a bit different from the games. In 2013’s The Last of Us, we meet Bill and learn about his former partner Frank, a man who took his after being bit when he left Bill. While Frank is never seen in the game (other than as a corpse) he’s played by Murray Bartlett (White Lotus) in the series, with Parks and Recreation alum Nick Offerman filling the role of Bill.

What we see from the two is a long-term relationship that begins after the outbreak. Bill, who was a survivalist and doomsday prepper even before the apocalypse, fortifies his small town after everyone evacuates and lives his life in peaceful solitude until Frank appears, looking for help. Thus began a decade-long love between the two, which took them into old age.

That’s where the story diverges from what we know. On the show, Frank never leaves Bill. Instead, the two of them grow old together. When Frank’s sickness leads to him being ready to end his life peacefully, Bill does the same so the two will never be alone. It’s such an emotional moment that’s heartbreaking as we are losing these two great characters, but there’s hope in the idea that you don’t have to be truly alone in this horrible world. More importantly, though, the episode is able to convey the couple’s entire relationship.

“I wanted to explore the idea of committed love,” showrunner Craig Mazin told GameSpot, TV Guide, and Metacritic. “That love is not something that happens immediately: There’s infatuation, there’s lust, we have these mind-bending moments with each other, but then over time, there’s this other thing that happens that is the product of commitment of time. And I wanted to see that because so much of what this show is about is love, in all of its forms.”

And interestingly, Mazin added that Frank and Bill’s love story is one that will resonate throughout the series. “In the creation of this Bill and Frank story, I think we put all of the themes and motifs of the whole series: You’re going to see some of these dynamics play [out] over and over, but, to me, they all echo out of Bill and Frank,” he said.

As for leaning away from established canon, executive producer Neil Druckmann’s rule of deviating from canon only when it betters the story is played really well here. “Episode 3 is a detour that Craig pitched me on, and the math I always do in my head is like, ‘The more we deviate from the journey from the game, the better it needs to be to justify that deviation,'” he said. “And I think that story, in particular, is so beautiful and moving and speaks to the themes that are explored in the game and the show about, again, the beauty and the horror and sadness that can come from love, that it just felt like a no-brainer to say, ‘Oh here’s this relationship that was just hinted at [in] the game, and we get to really flesh it out and see what it looks like and do some things that are different, in terms of where the characters end up, that I think really adds to the world of the show.'”

And while Frank and Bill may be gone now, they also play a major role in something from the game. After Ellie and Joel load up supplies and change into new clothes from their fenced-off town, we see them in the outfits from the first game. It’s a nice touch that adds another sense of importance to this particular story.

The Last of Us airs Sundays on HBO.