Three inactive Manhunters were stationed in each bunker while a section of the facility was dedicated to building more Manhunters. After Anti-Monitor unleashed a low level antimatter pulse, the bunkers all activated and Manhunter factories went to work.
On Earth, a Professor Chilton discovered a bunker on Tegra Glacier in California. Not knowing its true nature, he explored it just as the pulse passed through and was killed by Manhunters. Hal Jordan and Guy Gardner investigated the bunker and buried it in an avalanche.
After serving in the Honor Guard for a week, Jordan found another bunker with Tomar-Re in Tomar's assigned sector. Their testimony convinced the Guardians to assign Jordan to gather a small team and map out known Manhunter Bunkers.