A robbery rocks the entire household of No.6, and everyone is a suspect. Twelve-year-old trainee housemaid Alice and reclusive young aristocrat Theo are determined to solve the case. As they investigate upstairs and downstairs to track down the culprit, the mystery deepens and danger looms closer. Join them in an adventure spanning the grand streets of Belgravia to the Docklands of the East End in their headlong race to uncover the truth.