I think the film you're thinking of is INK (2009).
I thought of INK as well except the "someone/thing was killing those guardians/ppl and there of course were some other good guys trying to stop the killings b4 there were no more dreams" part doesn't really match. No mention of the main plot with the kidnapped girl. But maybe if kong only caught the beginning he might think that's the plot.
Anyway, does this look familiar?