England, late 17th century. A poor Oxford student, Justin Penrith, by chance saves the life of the nephew of an influential and wealthy man, Frank Madden, and becomes his mentor. However, on the way to the estate, the carriage is attacked by robbers. Having captured one of them, Justin and Frank learn about the untold treasure hidden by the famous pirate Tom Towney on an unnamed island north of Madagascar in a place marked by a skull on the rock... Joseph Allan Dunn (1872-1941) - American explorer of British origin and one of the most popular authors of adventure literature of the early twentieth century.