Confronted with a deep-sea base that is slowly imploding, Mia gets one step closer to solving the murder of her father. But things won't be that easy, as our small team of survivors but grapple with psychic jellyfish and exposure to mind-altering and potentially lethal pathogens that might just drive them insane before they can reach the surface. But even if they can survive all of this? The bigger question still remains - why aren't they allowed to surface?