[Jason hesitates as he thinks about how to word his answer. He knows Jon isn't going to like what he tells him. But perhaps it was best that Jon knows ahead of time. Jason isn't sure how much Damian is willing to say and Jon should know what he might get himself into if he finds Damian]

Apparently a nuclear bomb wiped out Metropolis. He didn't tell me what happened to the Kryptonians in that universe.