Strange anime about grand puzzle (6)
I believe the answer is:
enigma
'puzzle' is the definition.
(I've seen this in another clue)
'strange anime about grand' is the wordplay.
'strange' is an anagram indicator.
'about' indicates putting letters inside.
'grand' becomes 'G' (G is short for ground as in a thousand).
'anime' anagrammed gives 'enima'.
'enima' placed around 'g' is 'ENIGMA'.
(Other definitions for enigma that I've seen before include "It's mysterious, difficult to understand" , "Puzzling person/thing" , "Mysterious or puzzling thing" , "Puzzle of gamine (6)," , "WW two Ger. code device; puzzle" .)