The steamship Atlantica is heading for Boston, but dark shadows glide unnoticed under the waves in its wake. Your fellow passengers are behaving unnaturally, just standing and staring at the water with quiet longing. I am tormented by dreams of ghostly underwater nightmares. In addition, a passenger has now been murdered.

Suspicion, secret loyalties and twisted strategies rule the day! In the game Unfathomable, you control a steamer with your friends, but you can't trust everyone. As terrifying deep-dwellers emerge from the unimaginable depths of the ocean, any player can secretly be a vile cultist or a hideous deep-dweller hybrid. Don't turn your back on anyone - you'll need all your cunning to save the ship from the wave grave. Fight an army of deep-dwellers, unmask traitors, and lead Atlantica home in Unfathomable!