Tv shows -- plots and themes --

Has anyone ever recognized that a plot is reused? Of course, yes, especially with long-running shows, and many resulting in using pop culture film plots. But what I'm getting at is when for example watching a crime procedural -- the major episode plot is about searching for a kidnapped victim, and then the very next episode a major or minor character is kidnapped in some way?

I've observed there seems to be a two-episode block phenomenon. One episode is about one thing, and then the next episode has a similar [yet not exactly the same] theme, and then the next episode restarts a new "theme"? Or simply, one theme from the previous episode is present in the next episode into almost perpetuity.


I'm just wondering if anyone has observed this or something similar, and I hope I'm making sense.