Greg Starbuck and his father Dave dreamed of venturing from the San Juan Islands, Puget Sound in the North Pacific, aboard the Mary for the unknown and rugged waters of Alaska. With Captain Matt, father and son attempt to realize this dream but tragedy strikes the trio when Dave is killed in an accident aboard ship. It is up to Greg and Captain Matt to give substance to Dave's life by carrying out the original plan. Together they pilot the ship northward toward Alaska, taking on passengers en route. On this trip, Greg is initiated into the precarious and unpredictable nature of the sea as he comes upon ""surprise harbors"" and other sudden phenomena. Once in Alaska, the two try to sell their services and are hired by an important company only when they prove the worth of their ship and themselves the hard way, by saving a company official. This is a realistic picture of shipboard life with graphic descriptions of navigation as Greg learns the ropes of skilled seamanship. Too many climaxes reduce effectiveness to some extent.