On a dark night in the Danish harbor of Dragor, Ulf is handed a log-book by a lone sailor who then disappears. The bizarre events in the log lead Ulf and his friend Torben to make a dangerous winter crossing of the North Sea to Scotland in the 31-foot yacht Rustica. As they are passing through the Caledonian Canal, a lock-gate bursts open and nearly puts an end to their boat and their lives. Is this an unlucky accident or attemptd murder?