The Sign of the Black Dagger

What makes an ordinary dad just disappear? No note. No clothes missing. He just didn't come home from work. Will and Lucy are determined to track their father down. There are clues everywhere. A sinister stranger at the door. An empty office. And a two-hundred-year-old journal with a menacing black dagger on the front. To find their dad, Will and Lucy must uncover a family secret that's over two hundred centuries old - and discover the truth about the sign of the black dagger...