Kirk and crew land on a lonely planet where the sun is about to explode. They intend to evacuate the inhabitants but find the place deserted except for a Mr. Atoz who operates some sort of high-tech library. Despite trying to get a straight answer from him about everyone's whereabouts, Atoz is indifferent to their questions and insist they must quickly 'make a selection while there is still time'. They have no idea what he's talking about but wander about looking at the hand mirror-like disks on the viewers and they see images of the planet's past. Then, while a disk is in the viewer, Kirk runs through the doorway and is magically transported back in time to what on Earth would look like the time of Louis XIV (the 1660s). When McCoy and Spock follow, a different disk is in the viewer and they are sent to an ice age hell. All too late they realize that the library is a time travel machine and repository.<br /><br />While Kirk's visit is pretty short and not all that exciting, Spock and McCoy's is much more eventful, as Spock falls head over heels for Mariette Hartley--who was sent to this awful place as a punishment. The scenes with Spock are exceptionally interesting and very atypical of the normally logical guy.<br /><br />Spock's departure from the norm, the wildly inventive script and very diverse locales make this an exceptional episode--one well worth seeing.<br /><br />FYI--Ian Wolfe, the excellent character actor, played Mr. Atoz. I am a huge fan of older films and have seen him as a supporting and bit player in countless films in the 30s and 40s and he looked almost exactly like he did in this episode from 1969. Interestingly enough, despite looking ancient, he lived on another 23 years--dying at over 95 years of age!!