Many years ago, humanity's greatest nightmare was titans - giant beings that devour people, appearing from nowhere. The remnants of humanity built a huge protective wall, and life changed - calm and carefree living appeared within it. As it turned out, only for a time. Terror returns when a titan of unimaginable size destroys the wall, and the hordes of titans again tread on human territory. In the eyes of the teenage Erena, a monster devours his mother, and the boy swears revenge.