The tension is palpable in this gripping West Australian Symphony Orchestra production of Benjamin Britten's "The Turn of the Screw," an opera based on the well-known novella by Henry James. Soon after agreeing to mind a wealthy man's orphaned niece and nephew, a governess (Eilene Hannan) senses that something about the children isn't normal. But a series of strange events can't possibly be linked to the children -- or can they?