"When boarding-school student Oscar Drai meets Marina, she promises him a mystery and takes him to a secret graveyard deep in Barcelona, where they witness a woman dressed in black lay a single rose atop a gravestone etched with a black butterfly. Their curiosity leads them down a dangerous path, and they discover a decades-old conspiracy that puts their lives in the hands of forces more sinister and mystical than they could have believed possible"-- Provided by publisher.