“All Good Things” is based on a true story like the one Dominick Dunne used to tell so interestingly at Vanity Fair. Let me start with a brief summary, based on the film because I know nothing about reality. It involves David Marks, the son of a New York family who owned valuable 42nd Street real estate in the 1970s. The property at that time was rented out to strip clubs, porn shops, massage parlors and so on. Families, rich and private, move in the best of circles and the nature of their ownership is not widely known.

The patriarch, Sanford Marks (Frank Langella), is a bossy man. He often collects rent in cash. He expected his son to enter the family business. David (Ryan Gosling) doesn’t want to deal with that. A free spirit of the Woodstock era, he meets Katie (Kirsten Dunst), and together they escape New York and open a Vermont health food and organic products store called, yes, All Good Things.

Sanford stepped up the pressure. David gives up and returns to Manhattan, where his wife enjoys a life of luxury but is not happy. He finally discovered the nature of the family business. David, meanwhile, begins to change from the loving hippie he fell in love with. Their marriage split. Katie disappeared. He was never found again. David was suspected of involvement, but never charged, as he seemed to have an unquestionable alibi.

And I won’t reveal much more. The film is the work of Andrew Jarecki, who in 2003 made the wonderful Sundance-winning documentary “Capturing the Friedmans,” about a family and its secrets; father and one son were charged with child abuse. It’s easy to see why this story appeals to him.

The key to this film is in the character of David. One could imagine a scenario where an arrogant father encourages his son to rebel, but what is happening here is more complex and sinister. David seems to be adapting to the lifestyle forced on him. He played the role his father played between Manhattan power brokers and founding members. He and Katie lived in an expensive condo, attended charity events and so on. Perhaps it was his self-hatred that drove him to insist that they have an abortion.

Kirsten Dunst is so kind here as a woman who is at a loss to understand who her husband really is, and what the true nature of his family involves. The man she married and believed to have undergone the transformation of Dr. Jekyll. What happens is the kind of thing that develops only in fantastical horror stories, but the story does seem to have happened in one form or another, and the most incredible details of David’s transformation are specifically based on facts that come to light during two murder investigations.

I choose not to reveal how or where David met the beautifully named Malvern Bump (Philip Baker Hall). The nature of their relationship aligns with the place where they meet—the place where their lives are both at the bottom. Hall is one of those actors who seem to have inhabited their characters for years. He doesn’t need an explanation, because he just exists.

Jarecki offers a possible solution to the riddle of Katie’s disappearance and David’s alibi. It involves his mysterious friendship with Janice Rizzo (Diane Venora), and that’s enough about that. This film reminds me of Barbet Schroeder’s “Reversal of Fortune” (1990), based on the Claus von Bulow case of Dominick Dunne-able. In both stories, there are plenty of reasons to focus on the obvious suspect, except for the impossibility of explaining how he could have committed the crime: Indeed, if there was a crime.

I don’t understand David Marks after seeing this film, and I don’t know if Andrew Jarecki does. It occurred to me that on my first visit to New York of course I was drawn to 42nd Street, the port of entry for many youths from the province, and I might even have seen Sanford or David Marks. Little will I know.

By Raufs