The temperature hit 28 below zero early last week, but it was up to 8 above and spitting snow by Thursday afternoon when Jim Cottle, a mild-mannered schoolteacher from Silver Spring, set off across the frozen St. Marys River to a tarpaper shack a mile out on the ice.

Two spears lay on the running board of his borrowed snowmobile, a half-dozen wooden fish decoys were in his backpack and in his head was a scenario relived often since he left these parts to join the Army 20 years ago.

A big fish approaches his decoys in the clear water under the ice. He teases it in with a decoy on a string. With the other hand, he slips a spear in the water until the tines sit directly over the fish. Cottle's quick, powerful throw catches the fish just behind the head. Perfect!

Sound primitive and improbable? Two hours later, in the failing light of north country dusk, Cottle, a doctor of philosophy who teaches German and Latin at Largo High School, watched the tableau unfold exactly as pictured, with one regrettable change: He missed the fish clean, and in a flash it was gone.

So it goes in the wild country of Michigan's Upper Peninsula, where the wind hits heavy on the borderline and second chances are rare.

The St. Marys River lies in sight of Canada, 70 miles from the Big Two Hearted River where Ernest Hemingway used to fish, or said he did. (Locals claim it was the neighboring Fox that Hemingway actually fished. "He wouldn't give away his trout hole for any short story," they say.)

The Big Two Hearted and the Fox feed huge Lake Superior, which rolls down into Lake Huron at Sault Ste. Marie, dropping 20 feet through the St. Marys rapids.

In winter, the rapids stay open but the river freezes hard on both sides, halting seagoing ship traffic that in good weather passes here on the way to collect iron ore from Duluth, Minn. The ships stop, but the current never does.

"That's it," said Cottle, coming alive in the middle of a turbulent sleep that night. "I forgot to allow for the current. I threw behind that fish."

Cottle's four-day pilgrimage to childhood spear-fishing haunts was a trip back in time, except that time has changed little. The snowmobiles are new, he said, but the spearing is the same -- a shack, a stove, a spear, a decoy and a hole in the ice.

As a youth in the "Soo," as it's called, Cottle alternated between riotous public misbehavior and quiet private reverie in the spearing shacks. Once, on a high school hockey trip, he and his pals stripped their goalie naked, rolled him in snow and turned him loose in a hotel lobby.

There was drinking and wildness, but what he remembers best now at age 42, Cottle said, was sitting in a spearing shack, jiggling a decoy, watching the subtle shifts of light and shadow in the peaceful world beneath the ice and waiting for a big northern pike to roll in.

In the bitter winter, there was something extraordinarily soothing, he said, about staring through that hole at a world of sand and grass and fish contentedly swimming about, not even cold.

About a year ago, Cottle, who for years has made his own wooden fishing lures, decided to carve decoys like the ones he made for spearfishing as a boy.

He took a few early efforts to an Audubon craft show last winter and folks raved. Next thing he knew, he was selling wooden trout, pike, walleye, bass, sucker and muskie decoys and carvings for up to $160 apiece through the Museum of American Folklife in New York and big retail outlets such as Abercrombie and Fitch and the Orvis catalog.

He was carving and painting nice decoys, he thought, but the only place he got to test them was in a bathtub. He needed to see them at work.

Hence the trip to the Soo, where friends from a generation ago loaned him trucks and shacks and snowmobiles and acted as if he'd never gone away, except for the fish, which were not accommodating.

Cottle drove 30 miles down to Munuscong Bay, a northern pike hotspot, to fish the shack of a bear-sized, bearded woodsman named Ron Edgerly. "Last week, you could have speared 50," said Edgerly, "but it's slow now. Maybe the cold put them off."

With the little propane stove going, the door shut to keep out the light and the walls painted black, it was tomb-like inside the shack except for the spearing hole, through which a soft light glowed, reflecting off the sand eight feet down. Cottle dropped two decoys down, hunched onto a stool and jiggled away. The wind buffeted the shack. It was 2 degrees outside. Nothing came.

Eight hours later, a great northern pike rolled in like an angry bull, stopping inches from a decoy and fixing it with a deadly glare. Cottle was outside, tending to some baited hooks Edgerly had set. Alone in the shack was a neophyte whose shot missed by a foot.

It was three days, as it turned out, before Cottle ever speared anything, when a whitefish raced into his sucker decoy and met its fate.

On the fourth day, he sat bleary-eyed in Edgerly's shack on Munuscong Bay, watching the sandy bottom and pondering his misfortune. Four days, dawn and dusk, and he hadn't yet speared the first pike.

At 9:30 that last morning, just when hope began to flag, a pike rolled in, six pounds worth, a champion, and Cottle nailed it to the sand. Perfect.

The little prop plane took off that afternoon and rumbled south toward the Straits of Mackinac and the streets of Detroit. There was light yet left in the day and Cottle searched for shacks on the frozen waters.

"You know," he said as the plane crossed Munuscong Bay, "it sounds crazy, but if I could go back there tomorrow, I would."