The word that I found most fitting to these conditions is abstruse from http://wordnet-online.freedicts.com/definition?word=abstruse(Wordnet Dictionary):
From http://dictionary.reference.com/browse/abstruse notherAnother definition is (Dictionary.com):
Recondite (Dictionary.com) would be a very good alternative, with nearly identical meaning from http://dictionary.reference.com/browse/recondite:
I found this entertaining article at http://www.vocabulary.com/dictionary/abstruse(Vocbulary.com), which I think captures the meaning very well, and I’ll quote it fully:
The character Dr. Gregory House, of the U.S. television program House, (hat tip to Mari-Lou A) has a Holmes-like pit-bull tenacity (with all the same scariness to some) for resolving deadly afflictions. He was described in an article of the Los Angeles Times (Patt Morrison, July 20, 2012) this way: