It’s the perfect antidote to light-and-sunny summer fare: if you want grit, violence, and dark sexuality, turn to Unidentified Human Remains and the True Nature of Love, at the PTC Studio on Granville Island from tonight (August 27) to September 6. Canadian playwright Brad Fraser’s twisted tale of carnal encounters and a serial killer still raises eyebrows, even as it’s produced around the world. The edgy Twenty-Something Theatre mounts this production under the direction of Sabrina Evertt. We don’t need to warn you about the explicit language and nudity.