I think you are wrong... Till now all Ranbir films are on same plot - self discovery and search of love. Why will they use so much of VFX and mythology connection to show again the same self discovery and search of love.
This is story of Shiva whom Big B community safe guarding him so that he will search brahmastra and safe gaurd it from going into evil hands (mouni community).
I copied this description from IMDB
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