It’s the picture-perfect wedding weekend: The venue is dreamy, the weather is beautiful, love is in the air—and Willa Sullivan is having a bad time. She’s excited to celebrate her best friends’ finally having the big wedding they’ve always wanted, but this is the first time she’s seen her ex-fiancé in months, and he brought a date. Everything feels off, like she stumbled into an alternate universe. But things start to look up when Willa meets Danny, the groom’s charming and single childhood best friend. When they sneak off together, their rendezvous is interrupted by a masked killer terrorizing the reception. Willa and Danny fight to save the ones they love and survive the night, but the killer is unrelenting. A final girl Willa is not.

Or is she? She wakes up and it’s the morning of the wedding. She just had the most intense nightmare of her life. Only as the day unfolds, there are some uncanny coincidences that make her question whether it was really a dream, déjà vu, or something more sinister. After a horrifying turn of events, Willa comes to understand that she’s stuck in a loop of carnage and terror that she must learn how to escape or else suffer a fate worse than death—being an eternal wedding guest.