While on a routine cargo drop to the Tantalus Penal Colony, the Enterprise takes on a stowaway, the violently insane Dr. Simon Van Gelder. The episode’s one perfect shot depicts Spock preparing for the series’ very first Vulcan mind-meld while Dr. McCoy looks on. This shot is quintessential original series Trek – the concerned look on McCoy’s face as Spock is hunched over in deep meditation speaks volumes about the two’s relationship with each other. They team up to perform a risky procedure in the hopes of uncovering what’s really happening at Doctor Tristan Adams’ institute of horrors, and manage to save Jim in the process. Dagger of the Mind is one of the very first episodes I remember loving and remains a personal favorite to this day.

Next time Kirk demonstrates to Spock poker’s advantages over chess in ‘The Corbomite Maneuver‘.