WARNING: This article contains spoilers to “Horizon: An American Saga.”

Kevin Costner’s movie passion project “Horizon: An American Saga” dropped Friday on HBO after a blisteringly bad run in the box office. And it is clear to see why the first chapter of this franchise didn’t work in theaters, though not for the reasons you may be thinking.

“Horizon: An American Saga” is not a good film, but it would have arguably made one of the best television series in the history of entertainment. The three-hour first chapter of what is meant to be a four-part franchise series sets up Costner’s vision of the old West in a way I’ve not seen since the dawn of film.

To an old fart like me, the long exterior shots of pristine American landscape are stunning and well worth the time commitment, just not in a theatrical setting. The fact anyone involved in this production thought they’d get a huge audience to sit in a gross movie theater for three hours shows just how either out-of-touch or vanity-driven this project was from the off. But the overall story, acting and premise do work. Kind of.

The story centers on the lie of “Horizon,” a town that doesn’t exist in the middle of Apache territory. Those who venture there in pursuit of their American Dream, meet the same, violent fate. At the same time, we meet the Sykes family in Montana. Their world is thrown into chaos when their patriarch is shot (but survives) by his mistress, who flees to Wyoming with her young son.

Throughout these stories we’re introduced to every demographic of homesteader, including some faces from Costner’s former television series, “Yellowstone.” (RELATED: Kevin Costner’s ‘Horizon’ Makes Surprising Comeback. Did He Just Fail Up!?)

Had Costner cut roughly 50 percent of “Horizon,” including his own character’s storyline with the Sykes, and just focused on Sienna Miller, Sam Worthington, Luke Wilson, Owen Crow Shoe, Tatanka Means and the other incredible Native American cast who make up the true journey West, then maybe “Horizon” would work as a movie. But there was too much and too many people for this to be a successful modern movie for viewers. And the ending absolutely sucked.

Instead of a conclusion, we’re suddenly hurled from this total state of escapism into a jarring montage of what appears to be the rest of the films. While this may tease some viewers into wanting to watch more, it was just disappointing.

Ultimately, this first chapter of “Horizon” sets up a great ensemble storyline but feels more like an introduction than a fulfilling film. We meet so many different people, each of them contributing to what appears to be a journey to settle the West, with natural pathways for their stories to intertwine as the franchise continues. (RELATED: Sources Claim Kevin Costner Is Loving That ‘Yellowstone’ Won’t Work Without ‘His Genius’ Apparently)

Similarly to Taylor Sheridan’s stories, many of the richest characters we meet in “Horizon” end up dead before the credits roll. Costner, other than his own character, wrote a great script with Jon Baird. It’ll be interesting to see where they go with the second chapter. Now that we can watch it at our own pace, Costner may recover from the initial miserable failure of “Horizon.”

If you have basically an entire day free of distractions, I highly recommend giving “Horizon” a watch to make up your own mind: Is this film incredible, or does it harken to a time in cinematic history that has long surpassed the modern viewer?