Film director Steven Soderbergh says he faced a lot of challenges in making Mosaic, including what to call it. In January, HBO will air Mosaic as a six-episode series over five nights. But starting today, you can download a standalone app for iOS and tvOS, and take in its roughly 7.5 hours in interactive form, shifting your perspective among the story’s main characters in a branching narrative. Mosaic most resembles the sort of show you might binge-watch on Netflix — all of its episodes will be available at once — and yet it allows for a level of interaction only possible inside a custom app.

“It’s not a TV show, and it’s not a movie,” Soderbergh told me and two other reporters on Tuesday afternoon in San Francisco. “It’s something else.”

The creators have kept details about Mosaic’s plot a secret, thought it has been broadly described as a murder mystery. The series stars Sharon Stone as Olivia Lake, an author and illustrator; Garrett Hedlund as Joel, a handyman and artist; and Frederick Weller as Eric, whom HBO describes as “a suitor whose motives might not be genuine.”

Initial scenes introduce the characters. Then it’s up to you to decide whether to watch what follows from Joel’s perspective or from Eric’s. Along the way, “choice moments” will ask you to choose a perspective from which to watch the following scenes. The app also includes what Soderbergh calls “discoveries” — supplementary materials for the main story, including police reports, voicemails and emails between characters, and news clippings. You’re also free to go back and watch the story from perspectives you missed the first time around.

For Soderbergh, who won the Best Director Academy Award in 2000 for Traffic, directing Mosaic was a chance to play with the conventions of storytelling in a way that has long appealed to him. He is not interested in creating a Choose Your Own Adventure-style story in the ways Netfix is exploring, he says. But the interactive possibilities of an app appealed to him.

“I didn’t feel I was relinquishing control at all — it’s a fixed universe,” he says. ”I get to determine when those choice moments occur, and how they occur. I get to choose what the discoveries are, and how they pop up.” Viewers will be able to shift their viewpoint among characters at will, “and yet I’m still pulling the strings,” Soderbergh says.

Work on Mosaic started three years ago. The technology powering the app was built by a company named PodOp. Soderbergh developed it for HBO along with former Universal Pictures CEO Casey Silver and writer Ed Solomon.

Solomon, whose writing credits include the original Men in Black, says the creators hope Mosaic’s technology fades into the background. “The first thing we said is, let’s not sacrifice character or story,” he says. “Let’s not get enamored with the tech. Let’s try to tell a story about characters we really care about, with scenes that work no matter how they’re being viewed.”

The trick, Soderbergh says, was to introduce just enough interactivity to enhance the narrative without making it feel like a video game. But he was taken aback by the complexity of creating a branching narrative. The creators initially planned to include as many as 45 decision points, but scaled them back to a relative handful to improve the flow of the story.

“Other than The Limey, this was the most labor-intensive edit I’d ever been a part of,” Soderbergh says. “We did so much experimenting, rebuilding, and restructuring during the edit. When we started, we had over 40 [decision-making] nodes, and that turned out to just be too much — the runs weren’t long enough to really engage people and lock them into the characters and the narrative. We ended up simplifying it a lot.”

But Soderbergh emerged from the experience as a fan of the branching-narrative format, because it invited viewers to share the experience of a film editor. Seeing the same event from multiple perspectives can enrich viewers’ experience of the narrative, he says.

“In editing — which is my favorite part of the process, always — I’m always struck by how easily you can alter or invert the meaning of a piece mainly by changing chronology, and juxtaposing certain scenes with other scenes,” Soderbergh says. “It’s powerful to me how just moving a shot, and holding it four seconds longer, can change the meaning of a scene completely. This seemed to be a macro version of that, where the nodes are now the equivalent of those shots.”

Ultimately — and undoubtedly with some encouragement from HBO — Soderbergh decided to do his own linear edit of the narrative. It includes some scenes that aren’t available in the app. But he won’t call it the definitive take. “I don’t think either one is better — they’re just very different,” he says. “The app version is immersive in a different way than the linear version. Because I think there’s really no substitute for watching an hour solid, as opposed to a 23-minute chunk in which you’ve got these little discoveries. It’s just a different experience.” 

But at a time when unreliable narrators and questions about authenticity dominate the national news, Soderbergh says he does hope the interactive experience gives viewers an opportunity to reflect on the holes in their own perspective. He calls the experience of viewing Mosaic “a weird kind of empathy-inducer.”

“I’m curious to see, when people get to the end of it, if their sense of themselves and the world is tilted at all,” he says. “Because that was certainly something I felt, getting out the other end of it. It really makes you consider what’s going on offscreen in your life, with the people you know.” 

Soderbergh deadpans, then laughs. “We’re trying to unite humanity,” he says. 

You can download Mosaic here for iOS and tvOS. The Android version is expected to become available in the next few weeks, HBO says.