This story takes place several hundred years in the future, during an era where humanity is technologically advanced enough to achieve manned interplanetary space travel. The setting of the story is on Europa, one of Jupiter's moons, which has become colonized during the space age. Due to the surface of the planet being too irradiated for survival, colonies, and outposts have been established under the layer of ice covering the surface of the moon. Beneath the ice layer is a vast ocean, used as a transport network between colonies and as a source for natural resources. The ocean also allowed for the creation of transportation shafts that interconnect the colonies throughout the moon. The ocean itself is inhabited by a number of aquatic creatures, as well as naturally forming cave systems.
This is a story of a crew, hired to explore the dark sea of Europa, and expand the human colonies along the way. The crew members will be operating and maintaining a submarine, the Dugong. The crew is consisted with a commander, an engineer, a mechanic, a medic, and a security officer. In addition, there are aquatic creatures—arguably the antagonists of the story—capable of damaging the submarine and killing crew members, both intentionally and by consequence of damaging the vessel. Defending the submarine from these creatures and repairing damage they inflict before the vessel sinks could be considered the secondary objective.
The crew started their journey in a colony named Busan. The commander was given a mission of transporting a medical supply to the colony of Minos, next to Busan.
The crew has boarded their submarine, Dugong. And the crew about to undock their submarine from the colony of Busan.
The commander, Raymond Walker, is on the command room. The submarine's navigation terminal is offline. Raymond tells the mechanic to start the reactor of the submarine. Kody walks towards the reactor, while the security officer walks towards the armory. Rickie Shaw is seated in the armchair near the commander. Rickie is reading a book titled