Kevin Costner on $38M 'Horizon' gamble: 'Clearly things are at risk,' he says, but money can't 'keep me from my dream'

Kevin Costner has a lot on the line with his passion project Horizon: An American Saga, and no, not because he recently confirmed his departure from Yellowstone. The 69-year-old actor has invested $38 million of his own money into this film.

"Clearly things are at risk," the star, director and writer of the four-part western epic told Yahoo Entertainment. "I don't want to lose track of what moves me and what I want to do in my life."

The Horizon saga examines the Civil War expansion and settlement of the American West. To come up with some of the funds for the films, Costner mortgaged his 10-acre beachfront compound in Montecito, Calif. What's at risk isn't lost on the Oscar-winning actor, but he says it's worth it to pursue his dream.

"I had acquired those things, things that I never thought I would have. I'm keeping the things that are the most important — I mean, these are very important to me — but if they keep me from my dream, I can't be a slave to this other stuff I have," he explained. "So I put that at risk."

The first two films were shot back-to-back. Warner Bros. is releasing both and Horizon: An American Saga — Chapter 1 lands in theaters on June 28, with Chapter 2 to follow on Aug. 16. Chapters 3 and 4 have not been shot and are not entirely funded yet.

"I don't want to keep doing this," Costner said of carrying the financial load, telling Yahoo he hopes to "find a partner." But it's clear the actor will finish out this saga one way or another.

As for how Costner plans to measure Horizon's success, the actor said it's not all about making money at the box office.

"Success would be that, for me, that a man and woman says, ‘I want to bring our children even though it’s [an R-rated film]. I think I need for them to see what their great-grandparents went through.’ Even though it’s violent … there’s a lot of humanity in it," Costner explained. "I think success for me is people saying, 'I saw a really good movie last night, and I know there's another one coming. I want to see it again, and I want to share it.' So sharing is a sign of something that moves you."

On June 20, Costner confirmed his long-expected exit from Yellowstone, despite leaving the door open for a possible return just days prior. He hopes fans of the show, and fans of his, find joy in the Horizon saga, which he said is "designed to entertain."

"It was important for me to do my best in Yellowstone and try to support that, and to feel like these are stories that people would want," he told Yahoo. "In Horizon, it’s important for me to show that this isn't a land in Disneyland. This was a 200-, 300-year struggle. The second [film] is harder than the first one, I'm happy to say it's as good, if not better. … I think we're willing to watch that if somebody's careful with this in the telling of it."

Costner (Dances With Wolves, Silverado) is known for his roles in westerns, but overall, he's unimpressed with the genre. It's why he took Horizon into his own hands — literally.

"[Horizon is] not a story that was rushing to its gunpoint. It was a story where women were running right down the center of almost every storyline. … These things can move you in an American western, and I saw it and I wanted it in the writing, because that’s what I believe is possible when you watch a western," he said about the themes of the films that resonate with him. "I don't like a lot of them, because they're sometimes dumb or sometimes just too black hat, white hat. But this is really about behavior."

Horizon: An American Saga Chapter 1 is in theaters on June 28.