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, giving Suder a sense of calm by causing Tuvok to experience uncontrollable violent urges himself: he even attacks a holographic form of Neelix.
This episode also examines how a crewmember should be disciplined for a serious crime when home is so very far away. Confinement in the Brig is seen as barbaric due to the large amount of time he would have to remain there; it is also inconvenient because the brig would then have to be manned continuously. Executing Suder is discussed, but is rejected as both being in violation of Federation law and due to the fact that Suder was not mentally stable at the time he committed the murder. Ultimately, the decision is made to confine Suder to his quarters.