I'm bemused that so many reviewers seem to have missed the point of this stellar and poignant excursion into The Twilight Zone.
Brian Aherne plays Booth Templeton, an aging stage icon who dwells in the past, still longing for his late wife, Laura, who died at 25. The first day of rehearsal for a new play brutally catalyzes a trip backwards during which Booth is reunited with not only with Laura but beloved friends as well, all deceased.
While I'm not going to spoil the episode for those who somehow haven't yet seen it, suffice it to say that its point is ultimately NOT "the past isn't all that it's cracked up to be," or some such. The actual resolution, which is far more subtle and ingenious, is what fuels Booth with the resolve to move on with his life and leaves us, the viewers, glowing like a torch. See it for yourself and behold the glory of 1960s television at its finest.