Busiek, Leonardi and Daniel Green begin the Third Kryptonian storyline, playing off the observation about the number of Kryptonian on Earth by the Auctioneer, in Superman 668 (Early Dec. 07).
Superman finds Chris Kent, the son of General Zod and Ursa, who Lois and Clark have adopted, skipping school to have fun with his powers. He brings the boy to the Batcave.
Superman consults with Batman about hunting for any other Kryptonian on Earth, and also has Batman create a red sun watch for Chris, to nullify his powers and allow him to live as a normal kid. Chris winds up spending some time with Robin, and learns that powers are not needed to be a hero. Batman does track down another Kryptonian signature in the US.
A mysterious alien leads his crew towards Earth. This will be revealed later as Amalak, looking much nastier than his pre-Crisis counterpart. He is spying on Supergirl, and learns of the existence of Kandor.
The story continues in the next issue.