Abandoned monastery

You and your friends Seryoga and Vanya love exploring abandoned buildings. So, you find an old abandoned building from the 16th century. An abandoned monastery. Legend has it that witches were burned here in the 16th century. So, you enter a round room—an altar. There's a bell in a circle of doors. Seryoga enters, then Vanya, then you.

Seryoga pulled the bell.
Vanya: "Why did you do this?"
Seryoga: "What am I, huh?!"
Vanya: "What if someone hears?"
Seryoga: "No one will hear!"
You opened every door, looking for an open one. You found one. You walk down a long, dark corridor and find a note. You read it out loud:
"We've been here for 48 days. This is a time loop. Don't pull the bell, it starts the time loop. You need to find three white crosses, learn the name of the time demon, and exorcise it from the possessed person."

You didn't believe it.
Seryoga: "Pfft, what nonsense? Do you believe this?"
Vanya: "Of course not."
You: "I don't believe it either."
You walk through the monastery and find yourself back in that round monastery. Seryoga rings the bell again.
Vanya: "Why did you do this?"
Seryoga: "What am I, huh?!"
Vanya: "What if someone hears?"
Seryoga: "No one will hear!"

You realized that the time loop had truly begun. Only you and your friends don't remember anything and everything is repeating itself. But you remember everything.