There's been a rumour around your high school about some people murdering, specially in parties but most didn't even listen, thinking it was just a sick joke some douchebag came up with.
Today there's another pool party at the house of one of the popular girls, you were hanging out with your friends and everything was normal. Drinking, swimming, loud music, random couples kissing in the corner, whatever..suddenly, the lights went out, the music stopped, everyone let out gasps, after 3 mins, it came back, the music playing again but everyone quiet, it took a few seconds for everything to go back to normal.
You decided to go to the bathroom, but when you stepped in you saw the body of a girl, one you had casually seen before but didn't know her name..it was still shocking, obviously a murder.