Who is the Invisible Detective? To the people of London, in 1936, he's a shadowy crimefighter whose face has never been seen. Truth is, he's the creation of four extraordinary children who solve mysteries in his name. And neither an army of murderous zombie mannequins nor a subterranean monster can stop the Invisible Detective once the kids are on the case. Meanwhile, in present day, 14-year-old Arthur Drake finds the casebook of the Invisible Detective in a strange antique store. Stranger still, the casebook is in his own handwriting. With a little help from his grandfather, Arthur not only uncovers his link to the Invisible Detective, he soon finds himself plunged into mysteries of his own.