Riley's arrival occurs at the same time as Father Paul's (Hamish Linklater) first appearance on the isolated island. Though several miraculous events transpire after the priest settles in, things quickly turn sinister.
The Netflix miniseries concludes with a shocking ending that keeps fans guessing for a long time.
How does 'Midnight Mass' conclude? The ending, explained.
While the island's residents initially think that Father Paul is performing miracles thanks to his association with the Catholic Church, they eventually learn that he has been slipping blood from The Angel into the wine they receive at Mass.
Thi turned his parishioners into vampires, which explains why many of them were healed of their ailments.
In the seventh and final episode, "Book VII: Revelation," Erin (Kate Siegel) slashes The Angel's wings to prevent him from being able to fly toward the mainland. She then dies, and there are virtually zero shelters left on the island for the vampires to hide.
As the Dawn approaches, most of the vampire residents accept their impending deaths. They sing "Nearer, My God, to Thee" together as they wait for the sun to kill them. Bev (Samantha Sloyan), who had previously brought the vampires together to wreak havoc on the island, tries to dig a shelter for herself to survive. She perishes, as do all of the others who remained on the island.
The only two survivors are Leeza (Annarah Cymone) and Warren (Igby Rigney), who take a boat to wait out the Dawn on the water. Leeza was in a wheelchair before Father Paul's "miracle" allowed her to walk.
In the closing minutes of the episode, Leeza shares that she has lost mobility with her legs.
"I can't feel my legs," she tells Warren.
Though many fans interpreted the shift in Leeza's health to be a sign that The Angel died (and, thus, all of the healing properties in his blood were lost), creator Mike Flanagan offered another theory.
"We're not saying he died ..." he shared with The Wrap about The Angel's fate. "Our hope really there was just to say that Leeza's concentration in her blood had begun to tip back, that she was going to be OK. We didn't want it to confirm about The Angel, in that way that you can never kill fanaticism, it'll always kind of come back ..."
The conclusion of Midnight Mass is up for interpretation, leading some fans to wonder if there will be another season.
Will there be a Season 2 of 'Midnight Mass'?
Though a second season could follow Leeza and Warren as the only survivors from Crockett Island, Midnight Mass is currently listed as a limited series. Mike Flanagan's other shows for Netflix, The Haunting of Hill House and The Haunting of Bly Manor, were one-season works as well.
His next project, The Midnight Club, will feature many of the actors who were in Midnight Mass. Igby Rigney, Zach Gilford, and Samantha Sloyan are all set to have roles in the 2022 series, but it appears they will not reprise their Midnight Mass characters.
Midnight Mass is available to stream on Netflix now.