Content warning: This review includes discussion of, and 3 Body Problem includes depictions of, self-harm.

Adapting Liu Cixin’s science-fiction novel, The Three-Body Problem, is no small feat. The sweeping story leaps across timelines and bounces between the perspectives of a number of characters. All that goes to convey big ideas about physics and astronomy in the context of a mystery full of strange occurrences. Netflix’s series adaptation of the story, 3 Body Problem, succeeds because it takes care to tighten the scope of that vast narrative, focusing on the human element of its mystery and the people caught up in its weird events.

And there are a lot of weird events in the world of 3 Body Problem, starting with an apparent breakdown of science. High-level physics experiments suddenly no longer seem to work, and the greatest minds across the planet can’t make sense of the results they’re seeing. It’s as if the laws of the universe have become nonsensical, and the impact is so profound that physicists keep turning up dead, many seemingly taking their own lives.

In the series, much of that mystery falls into the laps of five genius physicist friends, who are reunited after their former teacher commits suicide, and the investigator trying to figure out what’s going on with all these dead scientists. It’s a departure from Liu’s handling of the story, which scatters a lot of the elements between more disparate characters. As a result, the reader sees the whole mystery, but the people actually wrapped up in it tend to get only smaller pieces, which lessens the impact somewhat on any of them individually.

This take, from Game of Thrones creators David Benioff and D.B. Weiss, along with The Terror: Infamy co-creator Alexander Woo, helps ground the story in a set of close relationships. The characters are original creations, although they also encompass elements of a few different characters from The Three-Body Problem and its two sequels, and their personalities and relationship with each other form the heart of the show. At times, the group and their role in the plot can strain credulity–a lot of strange stuff happens to the same handful of folks–but generally, it’s a smart change that lets the show linger on the characters’ reactions to what they’re experiencing, and that helps make it all more relatable.

Driving a lot of the action are excellent turns by Benedict Wong as Da Shi, the no-nonsense, former intelligence operative investigator trying to figure out what the hell is going on, and Game of Thrones alum Liam Cunningham as Thomas Wade, his gruff and callous boss. Both give the plot a powerful undercurrent that helps to balance the more immediate emotional reactions of the physicists. Wade is also another smart adjustment to the original story–he’s a Book 3 character whose enhanced presence in the adaptation helps to tie together more disparate events and make the wider plot more cogent.

The story revolves around a high-tech video game experience called Three Body, which sends players into a strange virtual world and gives 3 Body Problem room to flex its visual effects. Some of its coolest sequences take place within Three Body, which is set on a planet that is periodically annihilated by a fickle sun, with the show demonstrating just how astounding and horrific such an end would be.

Though those special effects moments are exciting, some of the best moments of 3 Body Problem are the emotional ones between the friends. Another GoT alum, John Bradley, is a standout as a physicist who used his genius to create a snack food empire, and lightens things up as the goofiest member of the group. Eiza González (Ambulance) has some of the most intense moments–her nanotech specialist Auggie finds herself seeing a floating countdown that nobody else can perceive. The interplay between the entire group, though, is the glue that holds 3 Body Problem together, and the ensemble helps elevate the material to keep even the most high-minded science-fiction ideas and moments feeling emotionally realistic.

A few complex theoretical ideas are essential to parts 3 Body Problem, and attempts to keep from getting bogged down in the science can sometimes undercut it. There are points when the science illustrates the stakes, and moving through it too quickly or too simply makes it tough to grasp why exactly everyone is worried. One of the best sequences relies on an understanding of a certain nanotechnology mostly discussed several episodes earlier, and if you didn’t quite follow what that technology is all about, it can make what might be the show’s most intense moment a bit of a head-scratcher.

That’s a minor complaint, though–for the most part, 3 Body Problem deftly dials in on the novel’s expansive story and ideas and keeps them approachable. What matters is how these ideas affect the characters in the story, and the sci-fi elements are compelling because the writing and casting keeps its stakes firmly human.

Netflix’s 3 Body Problem is a great adaptation of the source material, making smart changes so the story is easier to approach. It’s a deep and engaging story that maintains all the coolest sci-fi elements of the source material, while enhancing the humanity with its empathetic take on the original’s characters.