The Russian submarine K-152 Nerpa was three hundred feet beneath the Sea of Japan when a sailor on board noticed something strange. First one, then another, then another. Men were crumpling to the floor. Terror spread as hatches automatically slammed shut, trapping sailors inside.Something invisible was ripping through the vessel.The Akula-class nuclear attack submarine was only supposed to have a crew of 90, but now it carried over 200 souls into the darkness during its November 2008 sea trial. Alarms began to wail.However; the warnings, the indicators – nothing made sense. As the crew scrambled to grasp what was really going on, they couldn’t be sure if K-152 was trying to tell them something… or trying to kill them. The truth would almost be beyond belief…