May (Louise Krause) and Drew (Sophie Lowe), who seem to have a strained connection, are driving down a dusty road toward a secluded stretch of coastline where they plan to dive. Things proceed normally until a sudden landslide pins May beneath the water, leaving Drew responsible for keeping her oxygen levels up and freeing her from the rock pressing on her foot. The film has moments that are genuinely amusing—I sincerely hope their rental car was covered by insurance—and the underwater visuals do create a feeling of being trapped in a dangerously small space. However, as the plot unfolds, it becomes increasingly unbelievable, and I found myself wishing sharks would appear. Some unnecessary scenes showing memories of their father are woven into the main story; presumably to explain why their bond with each other (and with the water) isn't ideal—but the repetitive storyline quickly grows tiresome. The initial idea that May only has 20 minutes of air left made me think it might have been better suited as a short film instead of a full-length movie. I wouldn’t go out of my way to see it.

Source on TMDB