After completing Kamoshida Palace and stealing his heart, you will have a little bit of downtime. Even though we just got finished with a massive task, it is important not to squander any time in Persona 5. So use this day to hang out with Sojiro or Ryuji (who will be very antsy about what will happen with Kamoshida).
This will also be your first opportunity to do laundry post-dungeon, which will allow you to clean any dirty gear that you found. Once your time is spent, go to bed and prepare for the fallout tomorrow.
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