The movie starts with Gaby (Charlotte Rampling) driving, and she nearly runs over a man who was crossing the street. They exchange some words, but seem to take a liking to each other.
She meets up with Bert, a police superintendent; they're both dressed in formalwear. He stops at a crime scene that is particularly seedy. A dingy apartment, with a partially clothed dead woman in a bathtub full of water. The police on the scene think it was a suicide, but Bert points out it had to have been a murder. This death has no connection (that I'm aware of) to anything else in the movie, except to set the stage for the seediness to follow.
Bert and Gaby proceed to the opera, for which he has a great liking (along with white dresses). In the opera, the female lead playing Eurydice wears a sparkly white dress with lights beneath the cloth forming a large blinking red heart. Bert is absolutely captivated by the dress.
Bert insists on meeting the designer of the dress backstage, and it turns out to be Chris, the man Gaby almost ran over. Gaby and Chris become even more smitten with each other.
Bert persuades Chris to let him borrow the dress for a special friend. Chris goes along on the provision that he gets to do the dressing and undressing, thinking the friend is Gaby. Bert takes him to a well-hidden underground opera S&M club, populated by wealthy men and quite a lot of transsexuals. Performers lip-synch to opera songs. Gaby is not there, but Bert's love Pepper. A death occurs, and although Chris is innocent of it, it looks like the blame will fall on him, particularly when Bert forces Chris to make repeat visits to the club. Meanwhile, Chris and Gaby try to strengthen their relationship, which Gaby finds hard to do.
It was a pretty good movie, well-made. I'm sure the transsexual club limits its appeal, and be forewarned that there is some full-frontal male/female nudity - yikes....
