When his grandfather goes missing, ten-year-old Elkin Dab jumps in a cardboard box, leaves the real world, and sets sail for Graybar - a perilous island fortress. A high seas hitchhiker, a canine castaway, and a rambunctious sea bird lead Elkin to his grandfather. As he nears the end of his heroic voyage, he learns to cope with the inevitable loss of a loved one.