Loved the conclusion! At first I was a little sorry that Lois didn't know Clark's other identity previously but the outcome was so much better this way!
"Yes, actually, Superman. It's... well, it's about Clark actually. I'm really worried about him Superman. We had a spat at work yesterday, and then he went off on some investigation by himself, and he was supposed to check back with me but then he didn't even make it in to work this morning and I haven't seen him since and I'm really scared that something might have happened to him and I can't find him and I don't know what to do!"
Lois is quite the evil genius.
Lois blinked. "Run that by me again?"
Lois' saint fell down from the altar. Bad Superman, bad.
Indeed.
Her eyes widened and her jaw came unhinged as all of the pieces finally fell into place. "Cla- Wha--?"
He looked to his feet ashamedly, before glancing back up at her fury-filled face. "Um, hi Lois."
"Do you have something you'd like to say for yourself, Clark?"
"Uh, April Fools?"
Brilliant!!