The Flood (Halo)2003
by William C. Dietz
REACH HAS FALLEN.
THE COVENANT WAR MACHINE RAGES ON.
HUMANITY'S LAST HOPE LIES WITH THE CREW OF THE PILLAR OF AUTUMN―THE INDOMITABLE CAPTAIN JACOB KEYES, STAFF SERGEANT AVERY JOHNSON, THE AI CORTANA, HUNDREDS OF FEARLESS MARINES . . . AND SPARTAN 117, THE MASTER CHIEF.
Having barely escaped the battle for Reach, the crew of the Pillar of Autumn is forced to make a jump into Slipspace in hopes of evading the vast alien alliance hell-bent on wiping out humanity. But their destination brings them to an ancient mystery and an even greater struggle.
In this far-flung corner of the universe floats a magnificently massive artificial ring world…a construct from a long lost race. The humans' only hope of survival is to crash-land on its surface and take the battle against the Covenant...