December. A cold winter month that everyone would celebrate Christmas, Hanukkah and other religous holidays. But not tonight. It's Onew's Birthday. He is celebrating with a few SM family: his band members SHINee, the rookie band members EXO, and there so called baby sister Rin. As a snowstorm brewed in what are they going to do when each and every one of them is being killed one by one. Who is the killer?