He picked up Upali’s leather and canvas shoulder bag, the faded one Tusker had given him many years ago as a birthday gift. “It’ll help you fit in better here,” Tusker had joked with him. Upali had carried it throughout their college days in Michigan. A wave of sadness passed through Tusker as he opened it.

Inside was a notebook and laptop computer, along with an energy bar and a crumpled lightweight rain jacket. He pulled out the notebook and thumbed its pages, which were rippled and smeared from moisture. He found the last page. In Upali’s hurried, sloppy penmanship was simply a set of GPS coordinates and the word, underlined: “Helmet?”

Had they found a military helmet? If it was a navy vessel, this wouldn’t be unusual. So why had he questioned it?

Tusker set aside the notebook and pulled out the laptop, an old MacBook covered in decals. He opened it and booted it up. It was locked. Tusker cursed. What was Upali’s password? He tried to remember if he’d ever shared it. He tried a few configurations of “UpaliK,” to no avail. Then variations of “MOCHA,” with no luck. What was Upali’s mother’s name? His cat?

Then something came to mind. Back at Michigan Tech, he and Upali’d taken a course in deep-water shipwreck archaeology. The most famous wreck in the Great Lakes was the Edmund Fitzgerald, a 700-foot long freighter that sank in a storm in 1975. It was a case study in how to survey a deep wreck, since the ship lay in over 500 feet of water in Lake Superior. “The legend lives on, from the Chippewa on down, of the big lake they call Gitche Gumee.” The Lightfoot song. They’d just been singing last week in Galle. It was worth a try.

Tusker typed “gitchegumee.” The computer screen opened up. There was a series of folders on the computer’s desktop named for dates. He chose the last one and opened it. It was a series of video files with long, nonsensical names. He methodically began double-clicking on each one, watching the harsh, contrasty footage from what was obviously the ROV. It showed the Vampire. There was the bow railing; there was a nine-inch cannon. The crumpled superstructure. Incredible. But no clues.

Tusker yawned and looked at his watch. It was 1:30. He opened the last video. The ROV was approaching a hatch in the hull of the wreck. It went in, its landing skid barely brushing the edge of the opening. Damn, Suresh was good. The bright lights pierced the darkness inside the ship, and then, there it was. Tusker’s skin went cold.

He picked up the notebook again. Now it made sense. The helmet.

Exotic Gas

Four miles south of Batticaloa, Sri Lanka. The next day.