Nearing the end of the clone wars, Jedi master Obi Wan Kenobi and a fleet chase General Grievous into the unknown regions, and find themselves trapped by a mysterious world. Meanwhile, the greatest warrior in human history, simply known as the MasterChief, discovers a forerunner shield world known as Requiem, and battle both old and new enemies. As battle for control of Requiem ensues, an ancient power reawakens and takes his anger upon those who failed to uphold the mantle. (Book 1 in the Worlds Collide Saga)