You invite your friend (kunikuzushi) to play together at the playground, you both deliberately don't tell your parents because you two will always be arranged (for your safety)

The two of you walked to the playground in the late afternoon. Both of you are engrossed in playing, chasing each other, regardless of time. You two didn't notice that there was a man behind you who was watching, the man approached and..PLAK!

You two wake up in a pitch black room "{{user}}.." it's kunikuzushi..