Most of the time, documentaries don’t get sequels, which is strange. Unlike their scripted fiction counterparts, the story doesn’t end when the cameras stop rolling. If you’ve ever attended a filmmaker Q&A after the screening of a great documentary, you know the first question from the audience is almost inevitably either “What’s happened since?” or “Where are they now?” Bryan Fogel must have heard that more times than he can count in the five years since his game-changing Russian sports doping doc “Icarus” won the Academy Award. “Icarus: The Aftermath” is his response, a daring and sure-to-be-divisive movie that’s even more shocking than the 2017 original, even if the big news is already out of the bag.

“The Aftermath” follows Russian whistleblower Grigory Rodchenkov — former head of the Russian anti-doping agency RUSADA — for five years, embedding itself in the paranoid new reality that awaits him in the West after revealing inside knowledge of the elaborate conspiracy by the Russian sports establishment to cover up its use of performance-enhancing drugs. Incredible and enraging in equal doses, the project plays like a tense spy thriller as Rodchenkov is assigned a security team and shuffled from one safe house to another, while enemies of the state — Sergei Skripal and Alexei Navalny — are poisoned with the Russian nerve agent Novichok.

In retrospect, it’s kind of amazing that Fogel got the scoop in the first place. The point of his original documentary had been broader: to demonstrate that pretty much anyone could fool a doping test. “Icarus” was conceived as a “Super Size Me”-style stunt, of which Fogel planned to serve as his own guinea pig, taking the drugs himself and finding a way to pass. At some point in the process, he reached out to Rodchenkov and struck gold — the scientist had been suffering an ethical crisis for some time and decided to come clean — and Fogel reshaped his film around those bombshell revelations.

For the director, becoming the custodian of Rodchenkov’s secret presented an enormous personal responsibility: “Icarus” put his new friend’s life in danger, which meant that Fogel essentially had to help engineer his defection to the West, after which Rodchenkov was forced into hiding (for his own protection). During this process, Fogel obtained permission to keep filming. One cameraman, Jake Swantko, was allowed to shadow Rodchenkov, an exuberant, heavy-drinking character who tries his best to maintain some kind of optimism, even though it’s clear he’d essentially traded his freedom for a clear conscience.

And to what end? Shortly after the first film was released, the Olympic committee suspended Russia. That certainly sent a statement, though in practice, the penalty was mostly for show: At the next Olympic Games, Russian athletes continued to compete in certain sports (like hockey). A short time later, the Court of Arbitration for Sports reduced the ban from four years to two. Russia, it seems, was too big to bench.

Meanwhile, Rodchenkov had become a political target. Talking heads went on Russian state TV and insisted that he be imprisoned or shot. Putin gave an interview in which he said, “In general, treason is the greatest crime on Earth. And traitors should be punished.” No wonder Rodchenkov fears for his life. (In 2016, Rodchenkov’s No. 2 at RUSADA, Nikita Kamaev, died of a suspicious heart attack.)

In witness-protection sequences that may remind audiences of their own time in quarantine, Swantko films Rodchenkov drinking, exercising and dyeing his hair. The refugee makes video calls to his wife Veronika back in Russia, but the relationship is in trouble. Will they ever be united again? For a time, there’s a very real threat that Russia could attempt to extradite Rodchenkov back to stand trial. He applies for political asylum and considers undergoing plastic surgery. Reuniting with Veronika does not seem possible, lending a dimension of tragedy to their four-decade romance.

To keep from going crazy, Rodchenkov writes in his diary, which opens up one of the film’s most exciting subplots. It turns out, he’s kept detailed journals for almost 40 years, which are safely stashed somewhere in Russia. “Icarus: The Aftermath” shifts from spy thriller to heist movie for a spell, as Rodchenkov’s legal team sends an agent to retrieve these books, which corroborate his claims (which are reenacted via unattractive animated sequences). Since it’s easy enough for Putin to insist that they were all fabricated recently, Fogel films forensic scientists authenticating the journals.

“The problem of Russia is that no one can tell the truth,” Rodchenkov explains, insisting, “I’m not against Russia. I’m against systematic lying.” Remember, “Icarus” began as a film about cheating in sports; “The Aftermath” is a much bigger story, taking on the dishonesty, violence and intimidation of a corrupt regime. Say what you will about Rodchenkov and his motives (the Russian TV clips are brutal in this regard), but there’s something undeniably heroic in the sacrifices he makes to challenge Putin’s power.

The movie introduces others who feel the same, such as Yuri Ganus, new head of RUSADA, whom Fogel first interviews at the Play the Game sports conference. Despite enormous pressure from Putin and the Russian public, Ganus sincerely attempts to clean up the system. His efforts are not appreciated, to say the least, to the extent that Fogel asks Ganus whether he would also like to flee Russia at one point. Considering how central Fogel had made himself in “Icarus,” there’s surprising little of him in the follow-up. That makes it all the more powerful to observe the filmmaker in scenes where he and Rodchenkov are reunited. The earlier film had clearly bonded these two men for life. Coming clean in “Icarus” may have been a moral victory for Rodchenkov, but in many ways, this friendship is all he has to show for it.