I should have known the instant the dame walked through my door, two weeks before Christmas, that she'd be trouble. She was not what I might have expected. I'd have calculated short, dumpy, old; but if anything, she looked down at my 6'1" when I escorted her in; she was immaculate in her backless red dress trimmed with white, black stockings and matching red pumps; and she was young -- apparently, blonde -- probably, and a looker definitely. As she sat down, I could see teardrops like transparent pearls rolling down her cheeks.

"Mr. Barlowe," she said, now crying aloud, "I'm afraid my husband is cheating on me. Can you help me?"

"Slow down, ma'am," I replied. "Let's start at the beginning. What's your name?"

"Ingrid," she replied, and waited for me to say something. She was definitely a blond. She went on, "Oh, Claus, Ingrid Claus. I'm sure you know my husband, Santa -- everybody does." And at that she started leaking again. "He's been cheating on me, I'm sure."

I considered this. Then, "Go ahead, sweetheart, spill it all," and she did. Turns out she and Santa did it 364 nights a year. Santa was energetic, and there wasn't much else to do at the North Pole besides make toys and love. But on Christmas Eve, Santa left her behind. Ingrid looked at me pointedly, to see if I caught her drift. I did. Hundreds of millions of children to deliver presents to. That meant lots of mothers. Many single, or divorced, or just lonely; some drunk on eggnog, or with morals at a holiday ebb, or else just grateful. She was right about opportunity: the odds were stacked high in Santa's favor. If he were so inclined.

But opportunity, I pointed out, was no crime. "A woman knows!," she whispered, and started sobbing again.

I tried to dissuade her. Despite what she said, she didn't know, I thought, or she wouldn't be here. And keeping a tail on Santa - that would be dicey and then some. Plus, if she were right, it was maybe too much information to keep a lid on. Scandal. Headlines. Millions of people, children, would be hurt. "In my experience," I said, "people are better off not knowing. . . Come on Mrs. Claus, even if it's true, it's only one night a year. Even a good man's a man." At that, she broke down completely. And so, with an ample retainer in hand, I went after Santa. I'd stopped believing in him years ago anyway.

Santa would be a tough nut to crack. No one's allowed at the North Pole except Mr. and Mrs. Claus and Santa's elves. And when Santa's on the move, he moves fast. Hundreds of millions of deliveries in one night: the big package delivery companies could dream - but Santa was out of their league.

I wasn't a gumshoe for nothing, however. I had a reputation to maintain and a client to please - whatever that might mean. One sleepless night and a dozen neat scotches later, I had a plan.

I traveled to the far north, prowling lowlife bars above the Arctic Circle - Prudhoe Bay, Inuvik, Murmansk, Polyarny and a dozen other freezing gin joints - until I found what I was looking for. A nameless town in Greenland at about 80 degrees north latitude; a smoky bar; a group of unusually small men with watch caps over their ears and a greenish cast to their skin. One of them in particular sweating and twitching, hopped up on something besides the beer and vodka in front of him. I introduced myself and sat next to him. A dozen vodkas later, I made my move.

"So, you work hard."

"Damn right," he replied. "364 days a year."

"Pay alright?"

"Pay? Pay? It's a labor of love," he laughed bitterly. "The hours are non-stop, and so's the pressure."

"So," I said, "if you have to crank up a little, here and there, you've got good reason, right?"

He eyed me suspiciously, then said, slowly, "That's right. What's it to you?"

"Relax, I'm a friend. I can help you," I said, showing my cash, "if you help me."

$10,000 later, I'd turned an elf down the garden path for the first and last time. It can be a dirty business.

Two weeks later, back home, I sat in front of my computer on Christmas Eve and waited. The little black button I'd had the elf sew to Santa's red tunic should start transmitting soon. Satellite uplink, downlink, through hacked government computers, and ultimately out a system back door to my home in West Covina.

The screen flickered on and there he was, apparently holding his red tunic in front of him and moving it closer, until only his eyeball was visible, and then further away, so I could see his whole head and chest.

"Ho, ho, ho," he said, "testing, ho-ho-ho, testing. Darn thing seems to be working alright."

He knew!

"The real Mrs. Claus is not the jealous type, Mr. Barlowe," Santa said to the button. "You have not been a nice boy this year." Santa had that last part right, at least. With a flicker, the screen went black. And then, with a crash, my whole world went black.

It was still dark when I woke up. I had a lump the size of a walnut on the back of my skull, and the thugs who'd slugged me had also taken my computer. But the light had gone on inside my head. The dame had played me for a sucker!

A few days research on the web confirmed it. There, on the company website, was a picture of her, the tall, blond, sobbing, good-looker: Ingrid Clawson, executive vp of corporate affairs for a major package delivery company. The play: to learn Santa's delivery methods, or expose him as a cheating husband, or both. Either way, Santa loses, the delivery company wins. And if they steal the goods from me, it can never be traced back to them.

They'd figured me perfectly. And maybe to show me their long reach and to ensure I'd keep my mouth shut, the computer and books and clothing I'd ordered online that year were never delivered. But Santa, at least, was still out of their league: they got nothing on him, and my kids toys made it under the Christmas Tree just fine. It turns out, maybe, that even in this dirty little puddle of a world, it's still OK to believe in Santa Claus.

THE END