What's the plot of Mindhunter Season 3?
Mindhunter's first season took place in the late 1970s, with its second season picking up in the early 1980s. It's reasonable to expect that Season 3 would take place in the early to mid-1980s. That means that we could see any number of infamous serial killers on the show. We'll likely see more of the BTK killer, who's been seen in seemingly unrelated scenes throughout both seasons. Taking cues from the source material, it's also possible that Season 3 will feature appearances from the likes of Ted Bundy, John Wayne Gacy, or Jeffrey Dahmer.
Vulture speculates that, based off of the real criminals that FBI agents John E. Douglas and Robert K. Ressler interviewed in the past, we could also see killers like John Joubert IV, Joseph Paul Franklin, Donald Harvey, and Gary Ridgway appear in Season 3.
Aside from the investigations, there's also plenty of story left regarding Bill's adopted son, Brian, who was involved in a murder during Season 2. More vaguely, McCallany hinted to The Hollywood Reporter that Season 3 could be "a complete reimagining of the show." After two seasons filming in Pittsburgh, the show may move to a new location should it be picked up for a third season.