Five Spartan III's of Gamma Company get sent on a routine operation to investigate a forerunner construct within former Covenant space. What they found no one could have predicted or even believed. Meanwhile in Equestria, a peace summit is being held in Canterlot in the wake of King Sombra's defeat, bringing together the leaders of the world to welcome the reappearance of the Crystal Empire and discuss security in relation to Discord. What they got was a whole different brand of chaos altogether.