Book excerpt: When Sherlock and Amyus Crowe, his American tutor, visit Sherlock’s brother Mycroft in London, what they find shocks both of them to the core: a locked room, a dead body, and Mycroft holding a knife. The police are convinced Mycroft is a vicious murderer, but Sherlock is just as convinced he is innocent. Threatened with the gallows, Mycroft needs Sherlock to save him. The search for the truth necessitates an incredible journey, from a railway station for the dead in London all the way to the frozen city of Moscow—where Sherlock is entangled in a world of secrets and danger. InBlack Ice, the unstoppable teenage sleuth undertakes his third fantastic adventure, as one deadly puzzle leads only to another. Sherlock Holmes: Think you know him? Think again.