Fun story! I like the interaction between Lois and Cat. The whole dynamic between them has changed since Cat left. Lois isn't the frumpy, can't-get-a-man-to-save-her-life spinster anymore that Cat seemed to think she was.
(It occurs to me that my hyphenated adjective there has two meanings, both of which more or less apply.
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And, perhaps more importantly, Lois doesn't feel like a frumpy spinster anymore. She's got much more confidence in that department since she got together with Clark.
I'm assuming the unnamed blonde is Mindy Church, especially considering Bill, Jr.'s involvement.
Lois was awfully flustered by Cat when Clark left. She should have said something like Clark had a meeting to get to, and he took the stairs for exercise. She should blow it off, like, "Oh, Clark frequently takes the stairs when he's alone. That's how he stays in shape." That way, he's got a plausible excuse forever. Lois totally blowing it makes sense, though, given how stressed out she is and how annoyed at Cat she is.
Lois and Clark really need to sit down and come up with standard, reusable explanations for his disappearances and odd behavior. But that's more a commentary on the show and Superman in general than your story in particular.
