It has been ten years since Harmonic Convergence, and the world has changed. New threats have arisen that no single hero, even the Avatar, can fight alone. On a day unlike any other, Earth's mightiest heroes find themselves united against a common threat. It is then that they became the world's first group of heroes: the Avengers!

Four years after the end of the Human-Covenant war, the galaxy has changed. Humanity has taken its rightful place among the stars. Spartans have gone from being silent defenders to the vanguard of humanity's expansion. This role comes at a price, however. As humanity reclaims its ancient birthright, one Spartan team will stand at the center of it all.