Meanwhile, Spock is zapped by an exotic flower that is the real source of all this community goodwill, and he instantly gets happy, acting like a kid, renewing a romance with a comely biologist (an angelic Jill Ireland), and giving the sputtering Kirk an earful of entertaining insubordination. Story editor D.C. Fontana's script contains some obvious parallels between a chemically induced "paradise" and a drug-induced high in the 1960s. But the real draw here is Spock's uncharacteristic joy and the drama behind Kirk's shattering decision to break his friend's heart.

"Devil in the Dark" opens with an emergency on Janus VI, a planet rich in raw materials crucial to the running of Federation operations. There's a lot of money to be made by the mining contractor involved, but a swift, unseen monster is roaming the snaky tunnels of Janus's interior, turning miners into acid-drenched goo. It's up to the Enterprise crew to find the alien culprit and defuse the lynch-mob mentality spreading among the paranoid working stiffs there. Captain Kirk (William Shatner), Mr. Spock (Leonard Nimoy), and Dr. McCoy (DeForest Kelley) beam down to initiate the detective work, leading Spock to quickly conclude that the thousands of silicone balls mysteriously strewn about the planet's deepest level might have something to do with the reasons behind the atrocities.

Written by series guru Gene L. Coon and directed by mainstay Joseph Pevney (who alternated directorial chores with Marc Daniels during the show's second season), "The Devil in the Dark" is a breathlessly paced episode reflecting a delightful variety of cross-genre influences--Westerns, creature-features, gritty noir. Add one of the most effective and moving instances of the Enterprise's search for new life on Star Trek (plus McCoy's infamous complaint, "I'm a doctor, not a bricklayer!"), and this is a memorable program indeed. --Tom Keogh