Sulu, now fantasizing himself a musketeer, stalks the corridors with a foil and frightens off two crewmen.Deeper in delusion, he returns to the bridge and takes Uhura, declaring her a "fair maiden" (despite her protest that she was neither), under his "protection" before Kirk jumps him from behind and Spock subdues him with a Vulcan nerve pinch.Possibly related to People Jars, although usually more benign.
Sulu abandons the helm in favor of some exercise to "take the edge off," encouraging Riley to join him.
Riley remains, but soon becomes flamboyantly insubordinate to Spock, sporting an exaggerated Irish brogue.
The USS Enterprise orbits the planet Psi 2000, a world that was much like Earth in its distant past, tasked to observe the planet's impending disintegration.
Lieutenant Commander Spock and Lieutenant Junior Grade Joe Tormolen beam down in environmental suits to a frozen surface laboratory and investigate the horrific deaths of the lab's scientists.
Concerned about the planet's break-up and the crew efficiency needed to maintain a tricky orbit for their observations, Kirk asks if the surface tragedy could happen aboard the Enterprise. His mood quickly turns to despair and he turns the knife on himself.