My name is Caleb Renner, and until last spring, my grandfather was a photograph on my mother’s mantel and nothing more — a stiff, unsmiling man in a wool coat, standing on the deck of a boat called the Merrilee, squinting into a sun that set on him for the last time in the autumn of 1964.

He was thirty-four years old when he disappeared. My mother, Dorothy, was six.

The story, as it had always been told to me, was simple and terrible in the way that old family tragedies often are. My grandfather, Walter Renner, went out alone on the Merrilee on a gray October morning to check his lobster traps off the coast of Maine. A storm rolled in faster than the forecast predicted. The boat was found three days later, drifting and empty, twenty miles from where it should have been. No body. No note. No explanation. Just an empty boat, a coil of line still coiled, and a coffee cup wedged upright in a corner of the cabin as if nothing at all had happened.