When you follow that through, it seems pretty clear that the flashback at the end of episode 5 is building up to something. The Last of Us is well known for breaking the mould with its standout episodes, some of which — think episodes 3 and episodes 7 in Season 1 — take us on journeys into the past.

What happened to Joel and Ellie? Where are they? Is the Cordyceps brain infection still a problem? Catch up with everything from Season 2 of HBO's "The Last of Us."

HBO's The Last of Us has already filled season 2 with jaw-dropping, shocking moments. But none of them – including the death of Joel (Pedro Pascal) in episode 2 – have hit as hard as the twist in the final moments of this week's episode. And it all comes down to two, game-changing words from Ellie (Bella Ramsey): "I know."