WARNING: The following contains spoilers for Fear Street Part 3: 1666, now streaming on Netflix.
Fear Street Part 3: 1666 sheds a lot of insight on the untruths seeded out by the Goode family over centuries, slandering Sarah Fier as a witch so they could take blood sacrifices using slashers. It paints Shadyside as a true victim with Sheriff Nick the mastermind of so many innocent murders in recent times. However, while he gets his comeuppance and the curse seems to be lifted, there are some mysteries left unanswered when the trilogy ends.
Where is Deena's Dad?
Deena's dad was said to be working in Part 1, but as she assembles a team in Part 3, including Christine and Martin, to go after Nick at the mall, he doesn't factor in. He just leaves a post-it for them at the end of the film to hint that they've reconciled. Deena's dad was painted as a neglectful drunk, so it would have been interesting to have him helping out his kids. More so, when Deena was sent back in time to Sarah's body, we saw Sarah's father letting Sarah be persecuted without so much as a word, so it did foreshadow that Deena's dad would play a role to help her and fix the wrongs of old.
Why Didn't Sarah Leak the Secret?
When Sarah's caught by Solomon Goode, resulting in the bigoted town of Union getting ready to lynch her, she doesn't shout to high heavens that he's actually the witch. We have no idea why as she knew where his lair was, so even if the mob ignored her, her friends and dad could have gone to corroborate the twisted truth, thus freeing Sarah of her bad name.
Why Do Slashers Attack Nick?
Nick summons slashers to get sacrifices for Satan, and to silence those who know about his secret. We never learn, though, why they chase those who desecrated Sarah's grave and are marked. That shouldn't matter as they should be killing everyone. It's weirder at the end when Nick has Deena's blood on him and they attack him. While Deena's a desecrator of Sarah's bones, Nick's the overlord so he should be able to command them to stop.
Who Took the Book?
Nick's lair is cordoned off when he's killed, clearly the scene of a massive investigation. But someone steals this demonic tome in the post-credits, which leaves fans wondering if it's one of Deena and Sam's friends. It may even be someone linked to Josh as he was online spreading news of the drama from Part 1, confirming supernatural occurrences were plaguing the town.
Do Will and the Other Goodes Know?
The firstborn of each generation, like Nick, takes up the mantle of the witch, but in flashbacks, while they operate alone, it's never confirmed if other family members know. Will's benefited a lot as Sunnyvale mayor so it's easy to see him helping Nick protect their family's secret. If Nick's dead, the firstborn from the next generation could have swiped the summoning tome. The Goodes deny that they know anything, but they could be lying to the media.
What's the Possession Rule?
Nick picks people, as seen with Tommy, Skull Mask and later on, Sam, to either spill blood for sacrifices or to silence those who know his lies. But apart from Sam, his rationale seems random. Skull Mask (aka Ryan) was just a mall worker, while Tommy was a counselor whose ancestors were on Solomon's side, so he shouldn't have been an avatar. Sam's chosen to be near Deena and kill her, but he could also have possessed Josh, Deena and Ziggy to silence the crew as they hide out and plot against him, as possession doesn't seem to have a time limit.
Directed and co-written by Leigh Janiak, all three installments of the Fear Street trilogy are currently streaming on Netflix.