Daredevil has always been Matt Murdock's story. Over the last two seasons, viewers learned much about his past, from how he lost his sight, to how he lost his father, to how he lost Electra. Though both Foggy Nelson and Karen Page have been significant figures in the series (and branch out on their own in other series), fans have never learned their stories, until now. Foggy's entire family turns up this season. Karen's doesn't, but there's a reason for this. What's Karen's backstory? Warning: Spoilers for Daredevil Season 3 follow.
Episode 10, entitled "Karen," spends a great deal of time exploring her past and getting viewers up to date with how she became who she is. Viewers first meet her drunk, coked up and shirtless at a college party, but she's not actually heading to school. She's deferred, and from the looks of it, she did so to spend time with her dealer boyfriend.
But looks can be deceiving. Karen's really drinking and drugging to hide the pain she's in. Her mother died of cancer a few years back. Her father is a terrible businessman, attempting to run the family diner their mother left behind. Karen's brother, Kevin, is deeply concerned about his sister. He knows who she's running with, he's covering for her for being late. More importantly, he's going behind her back and un-deferring her acceptance to Georgetown. She needs out, and he knows it. He's not going to lose her the way he lost his mother.
But Karen doesn't see her way clear to leave this town. As much as she resents being stuck her, she's trapped herself mentally. She genuinely believes her father can't manage without her, and her brother needs someone to take care of him. She winds up lashing out at both of them for trying to help her, as they stage an intervention to push her to go to school. It's harsh, as Karen calls them both out and tells her father her mother hated their little one-stoplight town in Vermont as much as she does.
Karen's freak-out leads her to run off with Todd, her drug dealer, but Kevin follows. He can't stand to see her do this. Unfortunately, it all goes sideways. First Todd's camper catches on fire, causing Todd to freak and try to beat Kevin to death. Karen shoots Todd in desperation, and pulls Kevin away, driving for their lives down dark country roads. Karen is already high and drunk before all this started, and it doesn't take much for her to drive off the road and tumble the jeep over and over killing Kevin in the process.
Karen's dad, having lost both his son and his wife, does the right thing. He claims Karen wasn't in the car, Kevin was driving. The report is also doctored to remove any mention of sobriety. It's a kindness, which will keep Karen out of spending the rest of her life in jail or in Vermont.
Just one thing. Karen has to leave and never come back. Dad doesn't ever want to see her again. And from the sounds of Karen's phone call home even all these years later, he's not ready to let her come back.