Set on a military submarine deep in the ocean of an alternate 1970s Sweden, you must fight against the Sludge — an all-consuming filth that has turned your crew into horrific, oil-spewing zombies. Sneak through dark, echoing passageways haunted by the sound of your own footsteps, seek out survivors, and uncover clues about how and why your serene ocean workplace became, quite literally, a death can.