The Tokyo is ordered by Starfleet Intelligence to proceed into the demilitarized zone on the Cardassian Border to retreive the USS Cassandra, an Oberth Class Science Ship which has gone dark. The Tokyo sets out to find the Cassandra, venturing into the demilitarized zone. However on discovery of the ship the crew of the Tokyo find that every member of the Cassandra's crew lay dead from different causes. From suicide, to death matches between the crew down to just brutal murder. On returning back to Federation space, the Cassandra in tow nightmares of the Tokyo's crew start to come to life, slowly more and more terrors of the night come to life and begin to plague the crew. Then slowly the ships systems begin to fail as the Tokyo's crew is slowly pulled into the darkness...