Yesterday evening's episode of Agatha All Along was titled "If I Can't Reach You/Let My Song Teach You," and it starts by revealing that Sharon Davis/Mrs. Hart is indeed very dead.
The coven buries her and we learn that Alice Wu-Gulliver's mother once told her that travelling down the Witches' Road would be what saves her. However, the last time Agatha Harkness was there, only she and one other witch were left standing.
With Sharon gone, they summon a new Green Witch and it's none other than Rio Vidal! She rises from the ground like a zombie and a new house appears which is clearly themed around Alice and her mother's success as a musician.
It turns out Alice's mother would sing the Witches' Road song at her concerts in the hopes of opening the door. It never worked, and while they explore, Agatha and Rio try to call a truce; the former will get the power she desires, while Rio will get the bodies of those who fall on the Road.
A curse is unleashed and it's revealed to be the generational one which was passed to Alice from her mother. The coven has to play Lorna's ballad to save her daughter; she should have been burned by the demonic creature long ago but is kept alive because of her mother's protection spell. The power ballad kills the curse and the monster dies.
Teen, meanwhile, has been stabbed by a piece of glass in the chaos and collapses. Jennifer Kale manages to heal him and we learn she was once a midwife bound by a man who somehow figured out how to steal her powers.
Agatha, clearly worried about Teen, talks to him and explains that the Sigil also works on the witch who cast it so she doesn't know if she was responsible; however, it will lift when it's no longer needed. He then asks what happened to her son, crushing her hopes that he might be Nicholas Scratch.
The coven discusses past misadventures and Rio mentions that she once loved someone. However, she had to do something she didn't want to - even though it was her job - and it hurt them. "She is my scar," Rio says, likely referring to Agatha.
They seemingly let bygones be bygones but stop short of kissing. Rio then tells her "That boy isn't yours" as the episode ends, seemingly putting an end to any notion of Teen being her dead son.
Four episodes of Agatha All Along are now streaming on Disney+.