Now I'm sure with editing we're missing some of this plot but what I get is that Donghyun is Peter Pan and the girl is his Wendy. Sort of. Peter Pan and his group of Lost Boys are hanging out and for some reason Youngmin decides to make a bomb.They escape their garage/hangout and take the bomb to blow something up and happen to meet Donghyun's Wendy. Happy reunion commences but suddenly Wendy is taken captive by a strange man who takes the bomb Youngmin made so he can blow Wendy up. The members hold Donghyun back, because the green man has nothing more than the bomb to threaten the girl with, and then the bomb goes off and the girl blows up as does the green man, possibly. Donghyun is upset and decides to become Captain Hook.
I actually liked the song more than I thought I would so overall, I was pleasantly surprised with this whole thing. As always I'll be interested to see the live version because I always enjoy watching groups dance.
Last thing. Kwangmin, what was that thing on your head at the end of the video? Seriously? What was it and why was it there?