I don't want to give any spoilers so...
At the end of the game you will meet a mystery person. You talk to them and you find out you need to re-play 4 certain days.
1. Replay: Tuesday, September 22nd, 2020
2. Replay: Thursday, September 24th, 2020
3. Replay: Tuesday, September 29th, 2020
4. Replay: Sunday, October 18th, 2020
Make sure on day 11 to serve Freya the drink BedChamber instead of an expresso. Its not the drink she wants, but the drink she needs. *Thanks Kitty Skies
Achievement pops after you're done talking to mystery person again. If you replay those days and get dialogue you can't skip you're doing it correctly.