Superman: The Third Kryptonian #1

Superman enlists Batman to help him find the third Kryptonian on Earth, as detected by the Auctioneer. Chris Kent escapes from school, but Superman finds him and takes him with him to the Batcave. At Superman's request, Batman incorporates a red sun projector into a watch for Chris, to inhibit his powers while at school. Amalek, having heard of Superman from the Auctioneer, comes to Earth, and observes at first, discovering two other Kryptonians (Supergirl and Chris), and hears that Superman is looking for another. He decides to wait until all are found, to slay them all.