This is the end of the first mission of Halo 2, where the covenant have located Earth and begun their siege. At the time, Chief was aboard Cairo Station in space to be awarded for destroying Alpha Halo at the end of Halo 1. The Covenant attacked Cairo Station among other defensive space stations situated around Earth's orbit. After flushing the Covenant out of Cairo, Chief and Cortana discover a huge bomb the Covenant smuggled on board in hopes of destroying the entire station. With little time