A crewmember named Darwin is found dead and an investigation soon reveals murder. It is discovered that Lon Suder, a Betazoid, killed him, because he did not like the way Darwin looked at him.
To discover the reasoning behind Suder's admittedly senseless act Tuvok initiates a mind-meld with Suder. This causes Suder's violent impulses to be transferred to the Vulcan, with dire consequences. He even attacks a holographic form of Neelix.
This episode also examines how one can punish a crewmember when home is so very far away. Confinement in the Brig is seen as barbaric due to the large amount of time they would have to remain there, as well as inconvenient as the brig would then have to be manned. Ultimately, Suder is confined to quarters.