In an almost ironic turn of events, everything that Sabrina feared is brought to Greendale, and she has no choice but to accept what she was trying to escape this entire time.
During Chilling Adventures of Sabrina Season 1 Episode 10, the Dark Lord finally found a way to get Sabrina to sign the Book of the Beat. Madam Satan manages to convince her to do it in the name of her family and her friends, with the witches threatening the lives of everyone at Greendale.
But the aftermath of Sabrina's decision ends with her cutting off all communication with her friends and with Harvey. The future of many characters was left up in the air.
More importantly, though, the possibilities for the next season seem endless now, with Sabrina's sudden shift leaving not only Nick surprised.