The team investigates a large wooden shipwreck that could be one of the Bermuda Triangle area's earliest victims: the long-lost SS D.H. Mount. Just six months after the end of the Civil War, the Mount departs New York with 22 pro-Union politicians charged with rebuilding the post-war political structure of Confederate Florida. The ship vanishes in a stretch of water that will later be recognized as the Bermuda Triangle. The politicians had all received death threats ahead of the voyage. The wreck shows signs of a fire. Were diehard Confederate saboteurs to blame or could a steam engine explosion explain the damage? Or did an anomaly of the Bermuda Triangle doom this ship? The team recovers a series of artifacts that they hope will tell the tale...

The team has secret intel on a wreck that might be a legendary 1930s disappearance: the champion racing yacht known as Ingomar. Lured by a strange light, the Ingomar's seasoned crew smashes into an unseen obstacle, even though their charts show clear water. The crew escapes in a lifeboat only for the Ingomar to vanish behind them, never to be seen again. Now wreck hunters Mike Barnette and Jimmy Gadomski have found an artifact-rich wreck site that could be the long-lost yacht. Meanwhile, the rest of the team investigates the strange phenomena that lurk in the Graveyard of the Atlantic. What doomed the Ingomar?