When Kim Dan worked at the prosecutor's office, she used to make extra money by selling inside information to others. Although what happened exactly is not explained in detail, what’s known is that Lee Tae-joon(Yoo Ji Tae) finds out about what she’s been doing, threatens her, has sex with her, and then fires her. I don’t know if Kim Dan considers what occurred as sexual harassment, but it sounds like he took advantage of her sexually.
Although the situation is a bit different, the Korean #metoo movement was started by a prosecutor accusing a senior official, so there's some parallelity to the real #metoo movement too ¯\_(ツ)_/¯