Book excerpt: Once again, famous associates of the Great Detective – clients, colleagues and, of course, villains – tell their own stories in this collection of brand-new adventures. Meet Lucy Hebron years after Holmes’s only ever failed deduction; follow your nose down the streets of London with Toby the Dog; join Mrs Hudson on her first ever case; greet an ambassador from Mars alongside Lord Holdhurst; and confess your sins to your cellmate, Professor James Moriarty…