William Smith has a story. It’s hard to believe. Documentarian William J. Saunders spent four years with Smith trying to separate fact from fiction. So mundane that it’s fascinating, the tale that drew Sanders to Smith is too weird to be fully fictional. Supposedly, late one night, a mysterious neighbor named Roman handed Smith an incredibly valuable collection of stamps and then vanished. Something something something about a family in Los Angeles and a family in Arizona … a bad break-up … a temporary trip out of town. Smith, your average guy trying to make it in Los Angeles, didn’t know what he had on his hands, but he and Saunders (who had met at a dinner party) knew they had a story to tell. At the very least, it was a strange and exciting happenstance that would make for a good party story once Roman came back to get his stamp collection.

Roman’s trip out of town stretched days, weeks, months, years. Over time, Smith started researching the stamps in his possession and came to realize that the collection was incredibly valuable. Some single stamps were worth tens of thousands of dollars. Altogether, the bag of stamps could total in the millions. Along the way Saunders documented everything. The result is The Penny Black, named for the first postage stamp (which was in the collection), a true crime-style documentary where the crimes are only implied. It’s a soup of half-truths, innuendos and surprising reveals. Nobody, not even Smith, seems particularly trustworthy at first. After all, he’s telling an unbelievable story.

As is often the case with documentaries that start in hopes of finding a story, The Penny Black initially feels like a fabulation on the part of Saunders and Smith, trying to pull something out of the footage they’d shot over several years. That changes as the story focuses more on Smith’s anxiety over years of searching for Roman and trying to figure out how such a valuable collection came into his former neighbor’s possession in the first place. Was Roman a criminal? A mobster? A monster? Or just a strange man with a valuable collection desperate to hide it during a divorce? Is Smith’s life in danger?

It’s impossible to say for certain in this review, and even the end card of the film directs viewers to review follow-up material on a website for more closure. That’s really the sole critique, here: The final cards imply one ending and then immediately advertise another at their site. This seems like an unavoidable production problem due to locking the picture while the story was still ongoing, but one hopes a future edit could include more information on Roman and his reaction to the story.

The Penny Black starts as one type of low-budget documentary and morphs into something more intimate, fascinating and thrilling as it progresses. The situations Smith finds himself in — nay, puts himself in — are anxiety-inducing and feel real. He and Saunders find themselves in over their heads a little bit and take the audience along for the ride — all over a few books of stamps handed off by a stranger without any known reason. What an odd gem this is.