TOS - 3x02 - The Enterprise Incident

After Kirk inexplicably orders the Enterprise across the Romulan Neutral Zone, it is captured by the Romulans.
http://www.memory-alpha.org/en/wiki/The ... e_Incident


TOS - 3x12 - The Empath

On a doomed planet Kirk, Spock, and McCoy become the subjects of an alien experiment whose mysterious intention involves a beautiful, empathic woman.
http://www.memory-alpha.org/en/wiki/The_Empath


TOS - 3x17 - That Which Survives

Enterprise crew members are stranded on a ghost planet and terrorized by the image of a beautiful woman.
http://www.memory-alpha.org/en/wiki/That_Which_Survives


TOS - 3x18 - The Lights Of Zetar

At planetoid Memory Alpha, an Enterprise crew member's body is taken over by mysterious energy life-forms.
http://www.memory-alpha.org/en/wiki/The_Lights_of_Zetar


TOS - 3x19 - Requiem For Methuselah

While the Enterprise searches for the rare cure to a deadly disease, the landing party is confronted by a reclusive man who is willing to kill to preserve his privacy.
http://www.memory-alpha.org/en/wiki/Req ... Methuselah

The Enterprise Incident.

The Enterprise Incident.