Subnautica is a video game about crashing on an alien ocean planet outside of known space for unknown reasons. What you must do is learn how to survive off the strange planet, discover why you crashed, and escape the alien world. You start in your damaged escape pod floating by the Aurora ([left]the massive spaceship you crashed in, along with the rest of your crew) and must quickly find resources you need in order to survive.

As you progress in the game, your PDA pad will continuously warn you about rising radioactivity from the Aurora due to its power cells being damaged in the crash. At one point (usually around DAY 9) during that day, your PDA pad will warn you that the Aurora is about to explode and will start counting down from 10-1 and when it reaches zero...KABOOM! (see below) and then will continue leaking radiation, devastating the nearby enviorment.

As you progress even further in the game, a rescue ship search of the missing Aurora called the Sunbeam (see middle left) passes the planet your on and picks up the distress signal your pod has been automatically giving out for days for hope of rescue. The Sunbeam eventually establishes a landing site on a island for you to be rescued but, when you arrive at island you see a strange alien building (see third left)! When the Sunbeam arrives the building was actually a giant gun and then it blows the Sunbeam out of the sky! You later find out that the Precursors (intelligent aliens[see title]) built that as defense system because the planet has been put under quarantine by them due to the Kaharra virus (you later you see animals with green sists on them...including you![bottom left])