Sentence:  What the film rarely does is challenge or interrogate the fan culture to which it plays uncritical tribute. Wade and his friends, including a trigger-happy cyborgian alpha nerd whose offline identity the film handles more tastefully than the book did, are possessive gatekeepers, viciously protective of their pop-culture <WSD>wheelhouse</WSD>. 
Meaning of the word marked with <WSD> tags:  A person's area of authority or expertise.