Okay so what I remember is that it's in modern times. I'm not sure if demons are known or if they wear concealment. I remember that Sesshomaru and Kagome get stuck in an elevator. I think that it's because of Naraku, someone who has a grudge against Sesshomaru, and they can't get out in normal ways because there are explosives around the elevator. I remember that Sesshomaru works in the building and Kagome was only there because she had an appointment. It had something to do with planning her brothers wedding. I also remember that she had heart problems so that made the situation worse for her. She listened to music to keep herself calm so as not to aggravate her heart. I don't think she had any medicine with her and she was getting worse so Sesshomaru decided to chance busting through the elevator and building using his youki because she would die if they stayed any longer.
Other things I remember are that Sesshomaru comes to really like her and claim her as his, Inuyasha is with Kikyou (I think they're married) and he's a cop I think. Kagome had been taking medicine that was new to the market and I don't think her family knew. Kikyou is her cousin or some part of her family. And Naraku was nowhere near done with Sesshomaru and Kagome after they escaped the elevator. Oh and I believe it's a multiple chapter story and on this site, but I'm not completely sure if that.
I hope someone recognizes this story.

Elevator Romance by Vanessa? (RATED MA)
dokuga.com/fanfiction/story/8333/1?author=13495

That's it. Thank you so much.

You're welcome!