In the midst of a stand-off with the Rimulans, The Enterprise's computer systems, gain partial sentience, and with it, starts playing practical jokes upon the crew, which leads to a dangerous life-and-death battle with Romulans.
Did You Know?
This is the second consecutive installment to feature the concept of a practical joker, following the introduction of Ari bn Bem in the episode immediately prior to this one, "Bem". See more
The Romulans are flying in Klingon ships. Going by the stardate in Kirk's log, 3183.3, this episode takes place well before the TOS episode "The Enterprise Incident" in which the stardate is 5027.3 In the latter episode which takes place almost two years later, expository dialogue establishes that it was the first time Enterprise had ever encountered the Romulans using Klingon ships. See more
Lieutenant Uhura, I have to hand it to you. This is just what the doctor would have ordered.