Synopsis and Questions raised

"A couple of friends having a night out in the town when they stumble across an old building and thought it would be fun to prank one of their friends. Little did they know that they were pawns of someone else’s prank and things don’t seem to be funny anymore as each of them disappear mysteriously into the depth of the night..."

Questions raised:

• Who is that 'someone else'?
• Why did they enter that old building in the first place?
• How do they disappear mysteriously?
• Why can't they escape?