The story opens with director Brian Fogel, a competitive amateur cyclist, shaken by the revelations that Lance Armstrong had managed to dope and long avoid detection. Fogel concocts the kind of elaborate scheme that crowd-pleasing docs get built on: He'd prove that the system to test athletes was "bullshit" by doping himself — and then beating the tests. His search for a scientist who will assist him leads to the cheerily corrupt Rodchenkov, who proves eager to spill on camera the ins and outs of his Moscow lab's WADA-beating trickery. A hearty rapport develops between the American muckraker and the muck king of Russian sports.
But then news breaks of Moscow's state-sponsored doping. Fearing for his life, Rodchenkov flees Russia with the help of his new friend, Fogel. As Fogel interviews Rodchenkov about all the man knows, Icarus becomes something like an amateur Citizenfour. The Russians, of course, endeavor to discredit Rodchenkov, but their lies -- practically "Fake news!" -- are shredded by the footage that Fogel collected back when this was all a prank.