The origins and history of the Unsinkable Bandit Gang of Earth-Two are unknown prior to 1948.  Their first known case occurred in April of that year when they operating in the Great Lakes region of the United State. Dr. Charles McNider and his assistant Myra Mason had attended a medical conference in Detroit and decided to take a luxury steamer as part of their return voyage.  As there were relaxing on deck, Myra was shocked to see a car evidently driving across the surface of the lake.  The car pulled up alongside the ship and using grappling hooks, staged a boarding party.  While the crooks - known as the Unsinkable Bandits - raised the Captain's safe to steal some securities documents, McNider changed into his uniform as Dr. Mid-Nite and crashed into the Captain's office.  In the ensuing melee, the Doctor is blinded by a mirror sextant, allowing the Bandits to make their escape.  As they flee, they take Myra Mason hostage and when the recovered Mid-Nite gives chase, a well-placed shot dislodges a lifeboat and sends it crashing into him, forcing him beneath the waves while the Bandits flee.

As the car approaches shore, the passengers besides the driver seemingly vanish and the driver arrives an a rendezvous point.  As he waits, Dr. Mid-Nite, who had been holding onto the rear bumper, suddenly emerged and demanded answers.  After fisticuffs with the Bandit, Mid-Nite finds a map to the next rendezvous point and takes off in the car.  As he pulls onto the water, he makes initial progress before hitting an obstacle.  While he tries to determine the source of his impediment, the floor opens and Mid-Nite finds himself among the Unsinkable Bandits in the belly of a submarine.   The car, it seems, was simply a front for the largest vehicle of their crimes.  Again, a melee ensues Dr. Mid-Nite is knock unconscious and ejected out a torpedo tube.   The cold water revives the hero, who sims to the surface drops a blackout bomb into the sub through it's connection to the car.  He then follows it in and in the darkness, makes short work of the Unsinkable Bandits, who are then turned over to the maritime authorities (All-American Comics #96).

The later activities of the Unsinkable Bandits have not been revealed.