What is Accidental travel?

Accidental travel is a speculative fiction plot device in which ordinary people accidentally find themselves outside of their normal place or time, often for no apparent reason, a particular type of the “fish-out-of-water” plot. In Russian fandom, the trope is known under the term popadantsy, plural form for popadanets, female: popadanka, a person who accidentally finds himself elsewhere/elsewhen. The Russian term bears ironical flavor, because popadantsy has become a widespread cliche in Russian pulp science fiction. Russian critic Boris Nevsky traces this plot device to at least Gulliver's Travels. In Japanese fiction, the genre of accidental transport into a parallel universe or fantasy world is known as isekai.