The story of "Attack on Titan" is about a world where humans are being attacked, killed and preyed upon by unknown creatures called Titans. In front of these Titans, humans are left with nothing but despair, except becoming their food. So in order to protect themselves, humans live together and build a high wall that even Titans cannot climb. Humans have spent 100 years of peace in this besieged city, but one day, a super-large Titan suddenly appears and makes a gap in the high wall. This gap allows other Titans to enter the besieged city and prey on humans again. Just when humans think they are about to perish, the protagonist Eren Yeager unexpectedly turns into a Titan!!! Is Eren, who has turned into a Titan, a friend or an enemy? Can he become the last hope of mankind? Why can he turn into a Titan?