The Sub Killer that Creeped Out Japan

In May 1944, a creepy silence descended across the Japanese Imperial Navy's communications network. One by one, Admiral Soemu Toyoda's carefully positioned submarines—his eyes and ears in the Pacific—fell quiet.
First Ro-106. Then Ro-104 and Ro-116.

Five submarines had vanished in less than a week, leaving RO-105 as one of Toyoda's last hopes for his plan of trapping the American fleet.

As reports of the missing submarines reached Tokyo, Imperial headquarters dispatched urgent warnings to their remaining vessels.
Something was happening that had never occurred before in naval history. A strange new weapon was on the loose, and a mysterious American ship was somehow doing this all on its own…