In the summer of 1944, a stretch of water off the Philippines swallowed two American submarines, the U.S.S. Flier and the U.S.S. Robalo, taking more than 150 sailors down with them. Neither wreck had been found, and the exact cause of each sinking remained unclear. This episode of Dive Detectives follows the team as they dive the area, working under armed Coast Guard escort because the waters are known for both sharks and piracy. A deathbed statement from a retired U.S. Navy man reopens the search for the Robalo, and a hand-drawn sketch said to mark the sub's resting place becomes one of the team's key leads. The divers work through wreckage, historical records, and eyewitness testimony to try to pin down what happened to each boat and where it actually lies on the seafloor. The episode mixes underwater footage with archival material and interviews, building toward whatever the team's dives can confirm or rule out.