Andrew Haigh began getting a sense of the knockout power of his new film, "All of Us Strangers," a few days after it premiered at the Telluride Film Festival.

"I'd run into people who had seen the film three days before. I'd be talking to them and they'd just start crying," Haigh says, laughing. "And I'm sort of both apologetic and quite glad that it shook them to their core."

Haigh, the 50-year-old British filmmaker of "45 Years" and "Lean on Pete," is accustomed to strong responses from his films. His 2011 breakthrough, "Weekend," about a tender but brief romance, is considered a landmark of queer cinema.

"That that film has had an effect will probably always be the thing that I'm most proud of," Haigh said in an interview earlier this fall when "All of Us Strangers" was playing at the New York Film Festival.

Yet Haigh's latest, which opens in limited release Friday, may be his most shattering. Andrew Scott stars as Adam, a lonely screenwriter who, while toiling on a script, is transported back to his childhood home where he finds his long-dead parents (Claire Foy, Jamie Bell) as they were when Adam was 12. At the same time, Adam is hesitantly exploring a relationship with a neighbor named Henry (Paul Mescal).

The result is something magical and mournful that draws profound connections between familial love and romantic love, between gay life and estrangement, and between a pair of strangers nursing shared wounds. For Haigh, who shot the childhood scenes in the home he grew up in, it was also highly personal.

"I was entering my past as Adam was entering his," Haigh says. "The whole process felt like a slightly expensive therapy session."

Here are edited excerpts from the conversation.

Q: This is the first time you've attempted something in a metaphysical realm. Was it daunting?

HAIGH: It was really daunting. When you set a film, everyone's like, "What's it like? What can you compare it to?" And I knew I was going to be in for a tricky ride because I couldn't think of anything to compare it to. I'm obviously trying to do something different that is not really a traditional ghost story. It's a metaphysical realm, but I still wanted it to feel grounded.

Q: You depart from the Japanese novel by Taichi Yamada the film is based on, adding the romantic storyline. What lead you in that direction?

HAIGH: I loved the central idea in the novel about the parents but wanted to add this layer of this relationship and how that relates to the grief of losing his parents, wrapped up in the trauma, as he sees it, of growing up an outsider, growing up gay. I felt they meshed in a really interesting way. Those kind of traumas and pains and struggles can be linked. And I always wanted to tell a story about the pain that we carry around with us, and how easily it can come to the surface again.

Q: That was also the case in your "45 Years," where a longtime married couple is rocked when the husband's long-ago lover is found in a melting glacier. Both films have a frozen-in-time element.

HAIGH: I think all of my films are concerned with time. "Weekend" is set over 48 hours. "45 Years" is set over a week, yet it seems to go back in time. Time feels really unstable to me. You can be transported back 40 years just by hearing a song. And you can feel what it felt like when you were 12, you can literally feel it in your whole body. We're constantly haunted. The love that you feel for people that have been lost is as intense years and years later. It's exactly the same intensity of feeling. Nothing else is like that, that intensity.

Q: There's a scene when Adam tells Henry about his parents' death but says it was a long time ago. Henry replies, "I don't think that matters."

HAIGH: That to me is such a key line. I think for lots of things, we're convinced that we've gotten over them. We're told, "Time heals all wounds." But it doesn't. You feel it in your body, physically. You remember the pain you used to feel. We pretend we're OK but, of course, most of the time we're not. And we're still children. I'm 50 now and sometimes I feel like, "My God, I'm 10." How is that even possible? You're supposed to become an adult. When does this happen that I become an adult?

Q: One of the movie's most lovely moments is when Adam puts on his childhood pajamas.

HAIGH: Exactly. It's so absurd, that moment. We all still want our Christmases to be like we remember even if those Christmases were miserable at the time. We kind of have this strange nostalgic sense of what childhood should have been. I think for a lot of queer kids, there's a sense of grief that they feel that their childhood wasn't the childhood that they wished they could have had. There's a sort of mourning that queer people can go through wishing desperately for a thing that didn't exist.

Q: Did you feel that way?

HAIGH: Absolutely. I felt like an outsider for a very long time as a kid. It took me a long, long, long time to come to terms with my sexuality. I didn't come out until my mid- to late-20s. It took me a long time. And my childhood had some complications. I always felt on edge. And I think that's how a lot of people feel, whether you're gay or not. Lots of kids feel slightly estranged from their family.

Q: The way you introduce Jamie Bell's character — he seems almost like a potential lover — seems to immediately draw a connection between his relationship with Adam and Adam's relationship with Henry.

HAIGH: I feel really strongly that parental love is how you understand love in general. So it's bound to feed into romantic love. I always found that the feeling of romantic love is so similar to the feeling of love you have for your family. There's a difference, but they're so connected, which is is why it's so hard to forge relationships unless you felt huge amounts of love and protection when you're younger.

Q: I wouldn't want to give away the film's gorgeous ending, but I have to ask what pushed you to conclude it in such a cosmic way?

HAIGH: I do want it to have some kind of cosmic feeling to it. Someone said to me, "Stars can be dead for millions of years but you still see their light." A little bit cheesy, I guess, but, still, it's sort of true. Also as a kid, I never thought growing up in the '80s that I would be able to be gay and have a relationship and be in love. I thought it was an impossibility. When I was making the film, I was like: You know what? I'm going to make the sense of love massive. I want to go into the stars.