McCafferty recalls the true story of Ernest Hemingway’s stolen fishing tackle that inspired his sixth Sean Stranahan mystery, Cold Hearted River (Viking, July).

I heard about Ernest Hemingway’s steamer trunk, the lost treasure chest at the heart of my novel Cold Hearted River, from his oldest son, Jack. Jack and I were contributing editors for Field & Stream, and I’d bump into him while fishing British Columbia’s Thompson River. One evening, Jack hooked a steelhead in a run called the Graveyard, which was over the hill from a cemetery where graves were marked with crosses. I helped him land the great fish and we celebrated with a shot of schnapps in a thermos cup of hot chocolate. Maybe it was the steelhead (or maybe it was the schnapps) that gave me the courage to ask Jack if he thought his dad would have liked this fishing—that is, wading on slippery boulders in a river haunted by the dead, rarely hooking up, and considering the trip a success as long as you didn’t drown. He said that Ernest would have enjoyed the challenge, but that he’d lost the heart to fly-fish after a steamer trunk containing all his valuable gear was stolen from Railway Express in 1940 en route to Ketchum, Idaho.

Years passed, and I had no reason to recall that evening until my wife persuaded me to set a novel in northwestern Wyoming, where Hemingway had stayed at the L-Bar-T guest ranch in the 1930s. There, he hunted, fished, and wrote—among other treasures—most of For Whom the Bell Tolls. No one else had written a novel about the Hemingway connection here, to the best of our knowledge, and I’d had the premise of a story dropped into my lap.

Jack had died, so I turned to Patrick Hemingway, his younger brother, to verify the account. Patrick not only recalled the trunk but said that it contained top-quality bamboo rods and reels from Hardy Brothers, the famous London firm, and that he had helped his father convert pounds sterling into American dollars when he ordered from the catalogue.

It is, of course, one thing to be given a delicious page of history, and quite another to write it into a novel. For one thing, I had to find out what happened to the trunk, at least in an imaginative sense, and it took me a year to do so. And who was to say that the contents of the trunk were limited to fishing gear?