Thanks for the actor's name. Glad to see he aged pretty well hahahah
I think the video for Shake It Up has more of a couple of concepts than a plot. The lyrics say something bout getting lost in the dance, giving yourself to the music, don't waking up from a dream, so I think the PV is meant to be look like a dream or some delirium. The "doll" Kumi seems to be wrapped up and then when the music starts the music she sets herself free. The other two Kuu just look at her at the beginning, but then they start dancing with each other, and finally with the doll Kuu, all three together. I think that's kinda the idea.
