SPOILER ALERT: Do not read if you have not yet watched “For Heaven’s Sake,” streaming now on Paramount Plus.

Near the end of 1934, Harold Heaven went missing from his remote cabin in Canada. He was a man mostly everyone at the time — and even a few generations later — described as a perpetual bachelor and/or a loner. At the time of his disappearance, he was wearing a suit, carrying a rifle and walked out of his cabin but left his keys dangling in the open front door. Naturally, in the 87 years since, his descendants, and the rest of the inhabitants of the small town in which he had lived, have come up with quite a few theories about what really happened. The police report was stamped with suicide, but everything from drunken road workers to a dispute with a neighbor to alien abduction has been floated as potential truths at one time or another, and all of these theories are what Heaven’s great-great nephew Mike Mildon and his best friend Jackson Rowe set out to investigate with their eight-part docuseries, “For Heaven’s Sake.”

(Yes, even the aliens.)

“The journey of digging into everything came with its own consequences and came with its own benefits. For me, it was very much a journey of getting to know my family better, welcoming Jackson to our family, and there’s so much rich history that I had no idea about,” Mildon tells Variety.

Growing up, Mildon heard many theories about what may have happened to Heaven from different family members. The one that was the “favorite” in the family was that Heaven clashed with road workers who were hired to build a highway near his secluded cabin, so this became the theory that book-ended Mildon and Rowe’s series. In between, though, they explored varying motives for Heaven’s potential murder, including that these men drunkenly disturbed and then attacked him — perhaps because Heaven was gay, which was considered criminal at the time. As they considered motives, this often bumped them against other theories — some of which “built on each other,” Mildon points out — as well as other methods of disposing of his body, from dropping his body in a private lake to burying him under the new highway or in the woods, under what the Mildon family has affectionately come to call “the bump” over the years.

Pictured: Footage of the Paramount+ series FOR HEAVEN’S SAKE. Photo Cr: CBS2021 Paramount+, Inc. All Rights Reserved.

The filmmaking duo’s approach was to investigate anything that looked like a plausible theory, rather than set out to debunk them — with one exception.

“The only thing we really wanted to debunk was the suicide theory. We really didn’t think it had legs, and it would have been easy for us to show up and say, ‘This is wrong, we’re going to prove there was foul play,’ but as true crime fans [we knew] that it needs to be properly debunked before we can move on,” Rowe says.

Mildon and Rowe have a background in comedy. (In the docuseries they even show off an episode of their Funny or Die series “Trophy Husbands,” boasting that it had about 5,000 views at the time of filming. Now, though, it has more than 12,000 views on YouTube alone.) In order to stay true to themselves, they blended their humor into the tone of “For Heaven’s Sake.”

“True crime really does deserve to be treated with a level of respect, and that does suck a lot of the fun out of it because it’s a tragedy and it’s important and people’s emotions and lives are important. We learned about all of that, filming this,” Rowe says. “The little kernel of the show that’s different [is] we’re comedians; we’re an audience surrogate for some people. And we felt it was more entertaining with such an old case, where we can’t interview people who were around back then, [to add] little bit of spice to it, so that was poking fun here and there.”

“It was all the fun Errol Morris and those documentarians couldn’t have,” adds Mildon.

But while they recreated the road workers’ drunken walk to Heaven’s cabin to see if they’d lose their buzz by the end of it, and cut faces into apples in order to provide a rendering of a person about whom they were trying to learn more, their intention was to never “punch down on the case,” Mildon says.

“As funny as [the apple face] was, for some reason in the back of our minds, we were like, ‘This could lead somewhere.’ Because we had details on the flyer and we were hoping that would actually spark more of a memory than the actual picture,” he continues.

Pictured: Footage of the Paramount+ series FOR HEAVEN’S SAKE. Photo Cr: CBS2021 Paramount+, Inc. All Rights Reserved.

Every theory they put in the show were ones they “believed in” and “took very seriously,” Rowe notes. Again, yes, even the aliens.

“I personally loved the alien theory,” Mildon shares. “Growing up, the alien theory was so special and so well-ingrained in our family that I really wanted to dive deep into it, so we explored UFOs at the time and it was a very fun theory. But we had to ask that question, ‘Does it take away and does it make the audience lose trust in us that we’re actually trying to take this seriously?'”

In the end, the possibility Heaven was abducted by aliens only received a brief mention in an episode, leaving full interviews with psychics and people who claimed to have been abducted themselves on the cutting room floor.

Mildon is far from the only documentarian to look into a cold case in his own family (see Madison Hamburg’s “Murder on Middle Beach” as another example), but this story is unique in how even though he had access to the family and their land, the people he was interviewing grew up with campfire tales about Heaven, not the man himself. Mildon admits that he and Rowe took a lot of “hearsay and second-hand information as fact and ran with it.” They were “excitable,” he recalls — just eager to try to solve a mystery.

When they heard a man at the dump told Mildon’s uncle he knew who killed Heaven, for example, they looked at the likelihood of who would be at the dump at that time of day and ran with the idea that it was someone who worked there. Similarly, when they learned Heaven’s rifle went missing with him, they let the the narrative become that he was buried with it.

“We wanted to see Mother Mary in the toast,” says Mildon. “We so badly wanted to make [a true crime show] but we learned how they want to craft their own story, and we fell into the same trap. But what we like about our show is we come clean at the end and reveal something a lot of these shows don’t do, which is the impact they can have on the people involved.”

Mildon’s family had to put their trust in him and Rowe to do this investigation and tell their story, even when it brought up complicated questions about Heaven’s mental health or sexuality, or the possibility that another Heaven killed him. But his family also entrusted the filmmakers to quite literally go digging for the answers. Unable to tear up the highway and after striking out when renting ROV equipment and diving into the lake to look for Heaven’s body, the docuseries culminated with the men excavating the bump.

“When we showed them the GPR results the first time, it didn’t blow our minds as much as it did ours. They were like, ‘I guess you could dig it up,'” Rowe recalls with a laugh. But, he adds, “I think we owed it to the audience” to “pull out the big guns.”

“It was also the balance of active investigation with conversation because we couldn’t just information-overload the audience,” adds Mildon.

After 2 1/2 years of working on “For Heaven’s Sake,” though, Mildon and Rowe still don’t have the answer as to what really happened to Heaven on that fateful night almost nine decades ago, let alone why. “That’s why we came in so hot and that’s why we wanted to go to the local bars and talk to everybody and put up a billboard — because the more we talked about the case, the more likely someone was going to call our hotline,” Mildon says.

The hotline may be disabled now, but with the docuseries having launched on Paramount Plus, a whole wave of internet sleuths may want to look into the case, something with Mildon and Rowe both welcome.

“To this day I still think somebody knows the truth,” Mildon says.