Killing 7

In the reasoning network , there are seven members who share the common interest of reasoning. One day, they decided to go snorkeling for vacation. Unfortunately, they have an accident and drifted to a desert island. On the island, everyone's cell phones' signals are gone, so they are forced to stay for seven days until the next ship comes. The first night, six of them have received the missing partner's slaughtered video message at 0:10 midnight. The coming week, one person is missing night by night. Can some of them survive from the desert island? Or all of them must die there? Who is the murder? "Killing 7" will have a surprise ending for the audience.