The premise of The Man in the High Castle is undeniably fascinating. What if Hitler had won the second world war? What if America had been conquered by the Axis powers, and partitioned into a German-occupied east and Japan-controlled west? Amazon Studios’s newest show, based on Philip K. Dick’s 1962 virtual-history novel of the same name, is just as strange and horrifying as the dystopian classic, vividly realizing the what-if world Dick created.

Developed by Frank Spotnitz (best known for his many years of work on The X-Files), The Man in the High Castle is a fairly loose adaptation of Dick’s novel, taking in the entire scope of the Americas rather than just focusing on Japanese-controlled San Francisco and the “neutral zone” in the Rocky Mountains, as Dick did. Set in the 1960s, this is a world with swastika marquees in Times Square and a discomfiting (though obliquely remarked-upon) amount of racial harmony. It’s a world where a graying Hitler, now in his 70s, helps maintain a fragile peace with Japan that many think will expire upon his death. On a macro-scale, the series is absorbing, but it takes a few episodes to settle into the smaller stories that are unfolding.

The show’s hero is Juliana Crain (Alexa Davalos), a San Franciscan who gets sucked by her sister into a larger rebellion against the Axis occupiers. On the run from police, she ends up in the neutral zone with Joe Blake (Luke Kleintank), another rebel with secrets of his own (revealed at the end of the pilot episode, which Amazon first aired last January before picking up the series). Juliana knows Aikido and is introduced as a smart action heroine—an impression that’s undercut by her looking constantly confused as she’s swept up by events she doesn’t understand in the early episodes. Meanwhile, the most compelling thing about the square-jawed Joe is his secret, which takes a while to pay off.

Much more interesting is the alternate-history cold war developing between the Nazis and the Japanese, explored through high-powered figures like Nobusuke Tagomi (Cary-Hiroyuki Tagawa), a Japanese trade minister, and John Smith (Rufus Sewell), the head of the New York SS who’s trying to bring down the anti-Nazi movement. The show does a clever job of showing how rewriting history tends to create new monsters. Sewell in particular is terrifying as Smith—an American raised in a world of tyranny, the only thing distinguishing him from the countless Nazi villains of pop culture is his accent.

One of the themes Dick explored in his novel was the depressing sameness of post-nuclear geopolitics regardless of who the global actors are. Spotnitz seizes the opportunity to pick apart the mundane pragmatism of supposedly evil men, drawing fascinating parallels with real-life 20th-century history in his funhouse-mirror universe. As such, Tagomi finds himself caught up in covert efforts to stop Japan and Germany from going to nuclear war with each other over the occupied Americas. As the series progresses, other major plot points start to resonate with reality, despite unfolding in a surreal world.

It makes sense that The Man in the High Castle divides its time between political power players and the citizens whose lives they’re affecting. But outside of Sewell there are no dynamic performers here, and the hour-long episodes afforded by streaming television lead to some dull scenes that may leave viewers feeling antsy. Still, it’s remarkable to see a show like this on TV. There are moments where Amazon’s budget limitations show through—John strolls past a couple of CGI cityscapes that look like obvious green-screen inserts—but the overall attention to detail is admirable, and would have been unthinkable for a television series just a few years ago.

You can tell why Amazon has dedicated its resources here, too: The world of The Man in the High Castle unfolds best as a season-long binge-watch, adding strange, colorful details with every hour. It’s always a challenge to find an original way to depict the evil of Nazism, but the show feels up to the task. The future depicted is simultaneously banal and outlandish—a repressive police state, but one where men in Nazi uniforms appear on cheerful game shows. It’s that originality, building off the arresting premise, that stands out most of all.