Hello! 

My friends and I have figured it out!!!! I think

The blue flower bring people back to life!!!

1. The scene where Hyungwon wakes up after smelling and eats the flower...

2. The scene where they are in the bathtub... There was the part where Hyungwon's hand moved?

That might explain that party where they look high!? They were happy they found out the truth about the magical flower!

It will also explain why shownu brought the flower to the old man... But he was too late:(

I don't know what do you guys think?