WARNING: The following article contains spoilers for Marvel's Daredevil Season 3, streaming now on Netflix.
In the seminal comics storyline "Born Again," Wilson Fisk learns Matt Murdock's secret identity by chance after Karen Page, having hit rock bottom following a failed career in Hollywood, sells the information in exchange for a heroin fix. But in the third season of Marvel's Daredevil, Matt has no one to blame but himself.
Having mostly recovered from the injuries sustained in the implosion of Midland Circle, and regained his hearing, and thus, his "sight," Matt (Charlie Cox) learns that his archenemy Wilson Fisk (Vincent D'Onofrio) has not only turned FBI informant, but has also arranged for his release from prison and into a luxury safe house. Certain that Fisk is manipulating the government to serve his own goals, Matt becomes fixated on exposing his ruse, so much so that he begins to hear his rival's voice in his head, goading him and planting seeds of self-doubt. Although Matt had so far been careful not to reveal himself to his friends, he approaches Foggy Nelson (Elden Henson) in a bar, on the pretense of warning him about Fisk. In reality, however, he was stealing his old friend's wallet, and his New York State Bar Association ID, in order to gain entry to prison.
There, he believes, he can learn why Fisk has been providing information about the Albanian crime syndicate to the FBI. However, he ends up with more than he bargained for.
Whether due to hubris or recklessness, it apparently didn't occur to Matt that, although no longer behind bars, Fisk still maintains significant control over the prison, its inmates and some of its guards. Struck by a former client who's determined to make it known he isn't giving up the Albanians, Matt (believed to be Foggy) is whisked away to the prison infirmary, purportedly to be examined -- you know, for insurance purposes. Once there, though, he's attacked by an attendant and injected with an unknown sedative before he can overpower his assailant, as Fisk watches through a security-camera feed. Although Fisk expected Foggy -- he says as much in a phone call to Matt in the infirmary -- he's undoubtedly delighted by what he's presented with instead.