Every Little Thing STAR (PV)

[youtube=http://www.youtube.com/watch?v=ZIek9ugeKVw&sns=fb]
Credits: tpfyfl @ Youtube

The “Star” PV shows the plot from the perspective of the woman, but I don’t understand the plot. Two questions:
(1) What relationship does the girl in the wheelchair have with the male lead?
(2) Why did JKS suddenly become upset and leave the table at his party??

… again, the answer seems to be … wait for the subtitles or the “Moon” PV to be out, which will show the guy’s perspective.