The crew of an experimental underwater nuclear base are forced to struggle for their lives when their explorations disturb a creature who threatens to destroy their base.
A child psychologist, Hollis who's marriage collapsed after she learned she was barren, bonds with Luke Winfield, who witnessed his father's murder at the hands of rain-slicker wearing killer with a cargo hook. Along the way she befriends Detective Bass as he investigates a series of homicides, each with the same M.O. As Hollis gets closer to Luke she discovers some trouble family secrets ensuring she is next to be slain.