You're just a Yeoman sorting paperwork for the military submarine Sea Snail. It's a top-secret mission where the crew must retrieve a lost Deep Sea Vehicle from the depths of the ocean. All you need to worry about is sorting through all of the paperwork and keeping it in order.
Or so you thought.
Suddenly, you and the rest of the crew are swept up in a murder mystery as you try to figure out who among you can be trusted and who has some more sinister intentions for the survivors aboard the vessel.