From the back of the package:
EVERY LEGEND HAS A BEGINING
Welcome to Reach, heart of the UNSC's military power and home to the iconic Spartan super soldiers. For decades, humanity has fled from the relentless Covenant threat. but now the largest Covenant fleet ever witnessed looms in the darkened skies over Reach. Noble Team, equipped with a deadly arsenal of high tech weaponry and abilities, and bolstered by the full might of the UNSC, must stand and face a full scale planetary invasion with humanity's fate hanging desperately in the balance. If Reach falls, little will stand between the Covenant and the complete and total annihilation of the human race.
The fourth in the main series of Halo titles, and the last to be created by the original developer, Bungie. The game takes place in the year 2552, prior to the setting of Halo: Combat Evolved. The game focus on Noble Team, a UNSC spec ops team. Possibly slightly based on the popular "Fall of Reach" Halo novel.