Destiny is set in the 28th century, a post-apocalyptic future. The setting follows a prosperous period of exploration, peace, and technological advancement known as the Golden Age. In a universe where humans have spread out and colonized planets in the Solar System, an event known as "the Collapse" saw the mysterious dissolution of these colonies, the end of the Golden Age, and mankind teetering on the brink of extinction. The only known survivors of the Collapse are those living on Earth, who were saved by "the Traveler," a white, spherical celestial body whose appearance centuries before had enabled humans to reach the stars. The Traveler now hovers above the last safe city on Earth, and its presence allows the Guardians — the defenders of the City — the ability to wield an unknown power, only referred to as "The Light."