Berg had to interrogate his cast before hiring them: “Are you in physical shape?” Are your knees good? Are your ankles good? Is your back okay?” They were given a ‘cowboy camp’ for a month, during which they learned to ride horses in a meter of snow. Still one star, Taylor Kitsch, broke his foot on the second episode and was in a boot for six weeks. His lead, Betty Gilpin, still thinks about filming intense action scenes on horseback while in a corset for months. “Every time one of the boys started complaining about feeling uncomfortable in their costume, my hand would go to their windpipe,” she says. “I’m sure my liver is in my throat and my small intestine is in my ankle. Things have been rearranged in ways that will never come together again.”

Such visceral, violent realism helps with the setting American primal, premieres January 9, separately. The show is inspired by real events, where the clashing ambitions and fears of different groups in the American West come to an explosive head around 1857. “It was a very lawless, wild place in America,” Berg says.

All six episodes of Helming American primal, Berg chose the Mountain Meadows Massacre as the series’ instigator of tragedy. The first episode recreates the murder of hundreds of pioneers traveling from Missouri by Mormon soldiers on the orders of Church President Brigham Young. This is happening as indigenous nations, including the Southern Paiutes of Utah and the Northwestern Shoshone, fight for survival and safety in the same area where the Mormons are moving in.