Just when you thought nothing was free anymore and that quick service rated only a footnote in your kids' history books . . .

Linda Siadys of Riverdale was on her way to work the other day at the George Washington University Law Library. As she crossed 21st Street at G, the keys she was carrying in her hand fell.

That wouldn't be so bad for most of us. Just pluck them off the pavement and remind ourselves to squeeze a little tighter next time.

But Linda had gotten up on the wrong side of her astrological chart, or something. The keys fell directly down the sewer. Didn't pass go. Didn't collect $200.

Being a gambling man, I would have made Linda's odds of retrieving the keys about 1,000 to 1. It had rained recently, and the keys I know don't float. Besides, how could one hope to get anywhere near them in the first place? Knowing when I'm beaten, I'd have headed for the locksmith for replacements in a big hurry.

But less than an hour and a half after Linda's misfortune, James Brown of the District of Columbia government's water and sewer emergency service was handing the keys back to her with a big smile.

All it took was a call to 727-9103. Brown was dispatched in a D.C. government truck. He pried off the manhole cover and groped around in the muck with a pitchfork.

After four or five sorties, the pitchfork clanked against something metallic. James got underneath the something, lifted it to the surface-- and voila!

Best of all: there was no charge. James even gilded the lily a little by apologizing to Linda. He would have been out 45 minutes sooner, he explained, if he hadn't been stuck in a meeting.