Superman, Vol. 1 #662 (2007)

Camelot Falls, The Weight of the World
Disturbed by the mysteries that have surrounded him in recent months, Superman searches for answers. The Auctioneer told him that there were three Kryptonians on Earth. He and Supergirl account for two of them... but who is the third? And perhaps more importantly, is the presence of the Earth's defenders holding back a wave of evil meant to reduce mankind to a new dark age? And by holding that wave back, will it mean the extinction of the human race?
Release Date: 2007