When deep level oil fracking uncovers a vast subterranean sea, a crack team of cavers and scientists are sent down to investigate. Upon their arrival, they disappear without a trace. A second team, including sedimentologist Dr Megan Stoker, are ordered to seek out Alpha Team and report back their findings. But Alpha team are nowhere to be found - instead, they are faced with something unexpected in the depths. Something ancient. Something huge. Something dangerous. Predator X