In a future where humanity is exiled from Earth, Ezra Ashburn, a cadet for the Terrarian Military Defense, awakens on a planet reminiscent of Earth, 5000 years after Earth's destruction. Clad in one of six special armors, classified as "Reaper Armor", Ezra seeks revenge for the entity that annihilated his ship and causing him to become the last of mankind. As he explores the planet, he uncovers the past, revealing the dark secrets behind his planet's eradication.