Ten-year-old Siri and her little sister Miki live with their elderly father in an Arctic archipelago. One day, while they are out gathering snowberries, Miki is abducted by Captain Whitehead, a notorious pirate, who is rumoured to enslave the children he steals in a diamond mine. To prevent her father from risking his life to find Miki, Siri sets out to find her sister herself. In Siri's adventure on the seas she will encounter wolves, sailors and mermaids; profound evil and true humanity. Illustrations by David Barrow.