9 Most Memorable Alternate Universe TV Episodes 

ABC’s Castle always hovered on the edge of being a science fiction show. It even crossed the line a few times by hinting at the existence of ghosts, time travel, and alternate universes. The most memorable of these episodes is called The Time of Our Lives. Nathan Fillion’s title character is flung, via magical Incan artefact, into a universe where he had never worked with the NYPD, and had never forged a relationship with Beckett, Esposito and Ryan.

The episode itself is very much like It’s a Wonderful Life. Beckett is cold and distant because she and Castle never solved her mother’s murder. Castle’s relationship with his daughter, Alexis, is strained and distant, his own career has taken a nosedive, and he is forced to live with his successful mother, rather than the other way around. No real lesson is learned through the episode, other than that everyone’s life was enhanced by their relationships in the prime universe.

As is the case in any episode of Castle that delves into the science fiction realm, the ending makes the audience question whether it even happened at all. It’s a fun way for a mainstream show to explore the concept, and ABC executed it well.