"Breach the barrier. Stop Truth."
The Covenant is the title of the eighth campaign mission of Halo 3.
The level takes place on The Ark. In this level, the player must stop Prophet of Truth from firing the rings.
Before reaching Truth, the UNSC and Covenant Separatist forces must deactivate three towers powering the defensive barrier protecting the Prophet's citadel and face off against a massive vehicular Covenant force, including two Scarabs at one time.
Finally, united by the common purpose of stopping the rings, the Gravemind offers an alliance with Master Chief Spartan 117 and the Arbiter Thel 'Vadam, only to betray them once Truth is dead, while Cortana's solution to the Flood is finally revealed.