With its wonderfully poetic and sensual score, “Rusalka” is Antonín Dvořák’s most beloved opera, filled with musical effects that evoke the beauty and magic of a world inhabited by nymphs and water sprites. Jaroslav Kvapil’s libretto is based on a famously tragic children’s fairy tale, but in this acclaimed reinvention by directors Philipp Stölzl and Philipp M. Krenn Rusalka is depicted as a young woman from the dark fringes of society. She trades her power of speech to live in Hollywood at the side of a handsome movie star but is doomed to remain an outsider and a lost soul.