Underwater plunges viewers into the crushing depths of the Mariana Trench, where a routine mission for deep-sea drilling researchers turns into a desperate fight for survival. When a catastrophic earthquake destroys their underwater facility, mechanical engineer Norah (Kristen Stewart) and a handful of survivors must navigate through flooded corridors and across the ocean floor to reach safety. Their journey becomes increasingly perilous as they encounter mysterious, aggressive creatures adapted to the extreme pressures of the abyss.

Director William Eubank creates relentless tension through claustrophobic cinematography and sound design that emphasizes the isolation and pressure of the deep ocean environment. The film effectively blends sci-fi elements with creature-feature horror, drawing comparisons to classics like Alien but with its own unique aquatic terror. Kristen Stewart delivers a grounded, physical performance as the pragmatic Norah, supported by Vincent Cassel as the determined captain and T.J. Miller providing moments of dark humor.

What makes Underwater compelling viewing is its relentless pace and atmospheric dread. The 95-minute runtime wastes no time, beginning with immediate disaster and maintaining tension throughout the harrowing escape attempt. The creature designs are genuinely unsettling, and the underwater setting provides fresh takes on survival horror tropes. For fans of sci-fi horror and survival thrillers, Underwater offers a tense, visually striking experience that explores both the terrors of the deep sea and human resilience under extreme pressure.