Warning: This story contains spoilers for The OA season 2.

When it premiered in 2016, Netflix’s ambitious mystery series The OA explored the eery possibility of hopscotching between dimensions. At the dreamy center of the show, co-created by Brit Marling and Zal Batmanglij, is a character known as the original angel (the OA, played by Marling), who is fixated on the idea of crossing a “border that’s hard to define,” a goal for which she recruits a team of hardcore-believer, misfit companions. By the time we reach the curtain dropper of The OA Season 2, the show has taken that indefinable border and made it crystal clear.

By season’s end, we understand the endgame of Hap a.k.a. Dr. Percy (Jason Isaacs), the reason why Michelle Vu (Ian Alexander) disappeared, and the unique powers of BBA (Phyllis Smith).