#46. Lois and Clark try the adoption route again, sometime after their initial try. They are given the go-ahead after filing the initial paperwork. As part of the process, they both need to be fingerprinted for a background check. When Clark's prints are run, the computer makes a match - Superman's prints from years before when he was put in prison during the Metropolis heat wave.
#47. Bill Henderson searches Lex Luthor's home after Lois' almost-wedding. He finds the Kryptonite cage. Not knowing what he should do with the deadly substance, he turns to Lois and Clark for help, since they are Superman's friends. He brings out a stray piece to them to show them what he's found. Clark, already weak from his imprisonment, promptly passes out as soon as it is brought out.