The depths of the Mariana Trench, the world's deepest ocean trench, are surrounded by silence and darkness. The huge water pressure can easily turn three-dimensional creatures into two-dimensional planes. In such an extreme environment, a kind of fish survives - the Mariana lionfish. Forced to continuously evolve in order to adapt to the harsh environment, the eyes degenerate into decorations, the body is transparent, there are no fish scales, and the pressure of the internal organs is comparable to water pressure. Although they are lonely, they never try to give up their lives and live actively in the underwater world.