Weeks before Elizabeth Holmes entered federal prison after being convicted of fraud, the Theranos founder welcomed a film crew into her home.

The first teaser for the resulting documentary, "You Can See Everything," makes it seem like a mind-bending thriller starring the fallen tech visionary.

A24 surprised critics at the Telluride Film Festival on Sunday night with a screening of the closely held project, which had been kept under wraps for three years. It hits theaters in October.

Journalists who attended the screening wrote that phones and smart glasses were bagged upon entry. The festival director asked for secrecy on plot twists and a celebrity cameo.

"What happens in Telluride stays in Telluride," she told the crowd, Los Angeles Times reporter Josh Rottenberg recalled.

Comic Nathan Fielder and filmmaker Lance Oppenheim, whose A24 feature "Primetime" is also making the festival circuit, directed the documentary. Fielder's signature blurring of real life and character acting is on full display as he presses Holmes and her husband, Billy Evans, on whether they are telling him the truth.

A one-minute teaser shows an exchange between Holmes and Fielder. Holmes insists she has nothing to hide.

"I'm not that person," she says, adding that she is engaging with him "as a human being." Fielder then asks whether she is being real.

"I'm always being real," Holmes responds, unblinking.

At 19, Holmes set out to build a diagnostics company that could run a battery of blood tests with a few drops of blood. The idea took her from Stanford dropout to the Time 100, drawing comparisons to Steve Jobs and hundreds of millions of dollars from investors, including Larry Ellison and Rupert Murdoch. Then came a Wall Street Journal inquiry that exposed serious problems with the Theranos technology, setting off the company's unraveling.

Holmes was sentenced to 11 years in prison after being found guilty on four counts of fraud and conspiracy. Her projected release date is in 2031.

Here's what critics are saying.

Holmes says she did nothing wrong

Owen Gleiberman, Variety: "She resembles the '80s and '90s actress Kim Greist, and has a manner that's disarming in its gentleness. Yet when Fielder asks about the crimes she was convicted of, she pleads a strange kind of ignorance. She claims she did nothing wrong, and it's clear she believes it."

A Hollywood actor plays Holmes in the reenactments

Josh Rottenberg, The Los Angeles Times: "The movie takes a series of increasingly surreal turns, including elaborate reenactments involving a Hollywood actress (her arrival is too good to spoil) that further scramble the line between reality and performance."

Her husband is an 'unlikely star'

Kyle Buchanan, X: "You may think, 'Is there really anything new to say about Elizabeth Holmes?' And there very much is: Her partner Billy, a wild narcissist who emerges as the unlikely star of this film, is the most fascinating doc subject I've seen in ages. 3 hours and I could've watched 3 more."

The scene everyone is talking about

Pete Hammond, Deadline: "Fielder has a field day indeed grilling her and Billy who are willing, if wildly offbeat subjects here. In one strange scene he asks if they have ever heard of Abbott & Costello (no) or their comedy classic routine, 'Who's On First' which he proceeds to show them to elicit her bizarre interpretation."