Mark Gatiss 
Sherlock [PDF ebook] 
The Great Game #5

Sherlock admits defeat after failing to save the last hostage. John fears that Sherlock lacks compassion and is enjoying the deadly challenges. Shortly afterwards, the police discover a body washed ashore near Waterloo Bridge, which Sherlock immediately declares is part of the bomber’s game. He concludes that the man discovered a grave secret about a prized painting, which led to his assassination by a notorious hitman nicknamed Golem. John discovers that the victim had a passion for astronomy and, with Sherlock, they follow a trail towards a planetarium, fearing that the Golem isn’t finished.