The ML has a curse that during the day he’s a kid with no memories of who he is and at night, when he’s asleep, his body goes back to his adult self. Amy checks in on him once to see for herself if that actually happens and accidentally wakes him. She finds out that even as his adult self he has no memories of either who he is or the time he spends as a kid.
As someone else mentioned I think this promo is missing a few pages, I read a different translation of this before and remember it explaining more of the story.
When she told her sister to 'put him back where you found him', somehow the song from monster inc came in my mind, the song put that thing back where it came from XD
hmmm thats weird right... like hes technically a child then just transforms into a grown man at night so hes really technically a child... i dont like this i wanna get picked up before the fbi gets here...