The Harts find themselves in the middle of a dangerous murder plot, but it isn't clear if the plot it a famous author's fictional murder-mystery, or an actual murder plot, until Jonathan finds himself the unsuspecting target of a killer.
Hart to Hart: Secrets of the Hart
It Happened at the World's Fair
Demon Slayer: Kimetsu no Yaiba Mt. Natagumo Arc
Darkland: The Return