Karen Paige, Matt Murdock's former secretary and the woman he loved, had become a junkie. She had gotten so desperate she sold out Matt's identity to get her next fix. This info, of course, found its way into the Kingpin's hands. Slowly and methodically, Kingpin tortured Daredevil by stripping away his life outside the mask piece by piece. Eventually, he lost his law practice and his home, pushing Matt closer to the edge. Having enough Matt went to see the Kingpin with a taste for blood. But the belief in justice he held to so dearly for so long won him over, ruling out the possibility of killing Wilson Fisk. However, Matt was still going to hurt Fisk as much as the fat man had hurt him, despite that resolution. But unfortunately for him in his current state of mind he was easily taken down by the Kingpin and an "accidental" death was arranged for Matt. Matt escaped and began his slow climb back to sanity. But, with one decision all that could change...and somewhere, it did!
Matt arrives at Fisk's office and is led to his room, where along the way Matt "accidentally" stumbles into the guard helping him along. All it takes is a moment, some trigger, to let Matt fire the gun he lifted from the guard and shoot Kingpin square in the head. He waits until the heartbeat dies before leaving the soundproof office and heading out. It's only mere moments later Fisk's secretary discovers his body.
His rage subsided, the consequences of his actions sink into the mind of Matt Murdock. With one simple act he's made himself no better than the scum he just killed. As a man who believed in justice once, the only thing he felt he could do was turn himself into the police. Matt's frame of mind is at its most fragile. While he perceives himself confessing to a cop and standing trial (receiving what in his opinion is too lax a sentence) he actually confesses to a wino that spent the night in the tank at the police station.
Meanwhile, Ben Urich conveys the news of Matt's actions to fellow co-workers at the Daily Bugle; one being fellow Daredevil friend Peter Parker aka Spider- Man. Both men set out to find their friend in their own ways while the gangs of New York begin to riot without a Kingpin to keep them in check. Hobgoblin seeks to join in and make his move with his partner, Richard Fisk aka The Rose. However, the Rose seems a lot more remorseful over his father's death than one would expect; being that his sole intention was to one day usurp him from power. Hobgoblin didn't like this one bit, and absolved their partnership. Rose was confused about what to do or feel until receiving news about his mother's murder overseas, solidifying his new purpose: revenge on Matt Murdock.
Matt's mind further falls into madness as he perceives cops in riot gear to be monsters. He flees into an alley where the one heartbeat he manages to recognize coherently belongs to the only man who can save him now: The Punisher. However, instead of killing him as pleaded, Punisher offers him the assistance of mental help. Matt takes off just as Spidey enters the alley, perceived by Matt as a giant spider-creature. Even messed up, Matt was able to use both their efforts to stop him against each other and escape.
Elsewhere, Karen Paige was on the run from hit men sent after her by the Kingpin to keep her quiet. She managed to find solace in a church with Sister Maggie, until Paulo, the man who helped her stay alive in return for her being his forever, found her and shot her down. Never would she hear words of forgiveness from Matt Murdock.
Matt makes one last effort to get the sense in his life by confronting Richard Fisk, who was just setting out to track him down and kill him. Matt accepts either his forgiveness or his vengeance. Neither come as Hobgoblin, now working for Hammerhead, crashes in to kill Fisk. Matt stops him at the cost of both their lives, leaving Fisk to ponder the future. In Matt, he saw something he always wanted to be...the good man he forsake to become The Rose. Considering themselves even, Fisk grants Matt his forgiveness.
Weeks later, Daredevil is back on the scene, trimming down the gang war a little at a time. Richard Fisk returns to his friend Alfredo who checks the circuitry in his mask designed to mimic Murdock's radar senses before letting Fisk return to the good fight. Although he does not have the purity of spirit he saw in Matt, and realizes one day he'll have to pay for his crimes, for the foreseeable future he seeks to continue to do the work of a good man; to continue the legacy of Daredevil, the man without fear.