Last night’s The Last of Us Season 2 premiere on HBO gave us a tense therapy session between series hero Joel (Pedro Pascal) and Jackson’s resident (and only) therapist Gail (Catherine O’Hara). What made the mental health check in so frosty — besides Joel’s own inability to own up to the truth about what’s really driven a wedge between him and surrogate daughter Ellie (Bella Ramsey) — was the reveal that Joel had killed Gail’s beloved husband Eugene.

“You shot and killed my husband,” Gail says. “You killed Eugene. And I resent you for it. No. Maybe a little more than that. I hate you for it.”

Gail goes on to admit she knows Joel “had no choice” and she should forgive him, but she can’t, because of “how” he killed Eugene.

So what’s going on here? Who exactly is Eugene? Why did Joel kill him? Here’s everything you need to know about Eugene on The Last of Us Season 2 on HBO…

Who is Eugene on The Last of Us?

Eugene is a character who is mentioned, but never seen in The Last of Us II, the hit video game that the HBO show is based on. The Last of Us Season 2 is expanding upon his character in a similar way to how Season 1 gave star-crossed lovers Bill (Nick Offerman) and Frank (Murray Bartlett) more meat on TV.

Without getting into spoilers, DECIDER can confirm that we will meet Eugene later in the season and he will be played by Joe Pantaliano.

Now, The Last of Us is being deliberately coy at this point about what exactly happened to Eugene and how Joel killed him. However, we can confirm why Joel killed Eugene. Eugene was bitten by one of the infected, ergo he would have been turned by the Cordyceps virus. Joel had to kill him to prevent him from spreading the disease further.

The Last of Us Season 2 premiere ends with a few haunting developments for our heroes. Abby (Kaitlyn Dever) and her friends are closing in on Jackson, which means they are close to their goal of finding Joel. Elsewhere, Ellie has come into contact with uniquely smart infected who can stalk their prey. Oh, and it looks like there’s some Cordyceps sneaking into Jackson via the water pipes. They might want to take care of that.

Time will tell exactly how HBO’s The Last of Us tackles what went down between Joel and Eugene and what it means for the season overall…

The Last of Us Season 2 Episode 2 premieres on HBO and MAX on Sunday, April 20.