Things start off with the dapper yet oily carnival hypnotist Carlo Lombardi wandering along the beach and discovering a wrecked beach house with some dead people in it. It turns out that Dr. Lombardi is hypnotising Andrea Talbott to make her regress to a past life (making this the second movie in just three Mystery Science Theater episodes to try and cash in on the "past life regression" fad of the mid-1950s, the first being "The Undead"), but every time that happens she also regresses to her very first life, calling up a sometimes invisible monster from the sea. ("Donald Duck has the ring of power!") The heroic Ted Erickson (played by Lance Fuller, who had a small part in "This Island Earth") represents the good side of hypnotism and tries to win Andrea's affections; finally, the creature, who indeed has something kind of like female characteristics ("Ew! She's got prison matron bosom!") turns on Dr. Lombardi; doing the right thing at the very end, he manages to release Andrea from her final hypnotic state before dropping dead.
The episode did start off kind of slow for me; one thing I noticed that I do tend to look for in writing these posts was that there weren't many "quotable" "riffs" for me. For a while, I was almost distracted by wondering whether the dimness of the location scenes had to do with my copy of the episode or the movie itself, although there was a quip about that towards the end. ("We tried to light this, but this movie is like a super-absorbing black hole.") It seems that the "riffers" did have a good thing going in the unappealing Carlo Lombardi (in a "host segment," Crow creates a gruesome "Tickle Me Carlo Lombardi" doll), though, and as his unexciting hypnotic performances unfolded I did enjoy things more. A last-instant dash of nastiness towards the movie ("If I ever wanted to put a movie into a stumpgrinder, this is the one!") and the big question mark it flashes up on the screen don't seem to affect my reactions that much. In the "plot arc" of the eighth season, this movie has Mike blowing up "the planet of the Observers" through a casual, over-interpreted request to "the nanites," which manages to give Pearl Forrester her second sidekick.