This is a mostly spoiler-free review of Supernatural: Season 12, which is now available on Netflix. That is, until the end of the piece, where a spoiler warning will be provided. After the huge cosmic scale of Supernatural's Season 11 (that wound up being a strange, zero-sum game by the end), Season 12 brought things back down to earth in a effective, emotional way that involved the miraculous return of Mary Winchester (Samantha Smith) and the shady-turned-diabolical dealings of the British Men of Letters. Through this arc, the season was able to focus in on a handful of more nuanced themes involving family, wasted potential, and lingering resentment over abandonment.