Immediately after returning from their first adventure in Kilmore Cove, the land of Ulysses Moore, Murray, Mina, Shane, and Connor receive a postcard with an unexpected plea for help: the last rebel ship has been captured by the Imaginary India Company, which has taken control of the Routes of Imagination. To rescue it, you must find the Company's headquarters, a Dark Harbor that is not shown on any map. How to get there? The answer awaits Murray and his friends at Argo Manor, beyond the Door of Time...