Part 1: That wasn't very subtle

An alien by the name of Necrosse is given two tasks. First, he is to awaken and apprehend a legendary emental by the name of Excalibur. Second, he has to unleash a bio-weapon known as Hellific, a zombie-like disease that causes the victims body to enter a stasis. However, when Necrosse arrives on Earth, he realizes apprehending Excalibur is going to be harder than he expected.
Meanwhile, the lives of 3 teens are turned upside down when an alien shows up and causes the end of the world.