(Original Publication Date, 18 January 1991)
Panel 1: The next day, we find Mr Noname telling Liz (who's got that "please pity me" look on her face she adopts when she's trying to evade punishment for failure) that he can't give her a grade for a homework assignment she didn't bother handing in. She says "I know" because neither of them realize that he can for sure give her an F-minus for not doing any work at all.
What this means is, of course, that he is supposed to give her yet another extension to sleepwalk her way through in the hopes that John will do her work for her so he can feel like a big hero. He's a fink because he does what normal people do.
Panel 2: When he asks what happened, she tells an oddly plausible story about how she got locked out, went in through a window and left her books on the porch. The binder blew open in the wind and her homework got wet so her brother put it in the dryer only for her mother to throw it out because she thought it was paper out of her dad's pockets.
This sounds to him like Liz trying to lie her way out of a failing grade by coming up with a plot that he'd dismiss as being totally unrealistic if he saw in on television. It sounds to me like a zits-and-vacuuming arc.
Panel 3: We deal with his having correctly guessed "I sat on my ass watching television because I'm on strike for some reason my idiot parents can't fathom" when she tells Dawn that she'd hoped he'd have given her a few marks for her excuse.
Summary: We find out why Liz says she is failing class tomorrow when she's dealing with the message John and Elly don't realize that they're sending. Said message is "Ha-ha! Your childhood is OVER!!!"