Four strangers find themselves haunted by the same dream: being dragged to a drowning death by the Nartressan seaweed. Despite their different ways of life, they all have one thing in common.
They investigate the origin of the dreams and discover that the mysterious entity is not only more vicious than previously believed, but something else altogether. Things escalate quickly, as reports of drownings and ships under attack reach the media.
After the four discover an abandoned underground research station, they embark on a mission to unlock the terrible secrets hidden in the shuttered facility. What will they find there, and will it answer the mystery of their dreams?