An alien virus picked up from the now-dead Psi 2000 outpost strips the crew of their inhibitions, causing chaos as each individual is overcome by hidden emotions--even Spock. Meanwhile, the disabled crew have left the Enterprise unable to react to the planet break-up below that is pulling them down. The Remastered edition now offers the exterior of the doomed Psi 2000 station, the viewscreen shots of the ever-nearer planet are more realistic and intense, and even the ship's chronometers get an updated but still "feel right" look.