An oddball collection of memorable characters populate “The River Why,” a bizarre tale set in northwest Oregon from the 1950s to the 1970s.

There’s the effete Henning Hale-Orviston, stuffy world-renowned flyfishing writer from the Portland suburbs with a vocabulary straight out of Shakespeare.

There’s Carolina Carper, a raucous Eastern Oregon cowgirl “crane-and-cable” worm angler with a vocabulary straight out of the lower tiers of a Naval cruise ship.

The couple’s unlikely meeting on the banks of the Deschutes River sets off a series of events, not the least of which is the birth of the narrator, Gus Orviston, and his upbringing neck deep in fishing gear and a Civil War of styles between H2O and Ma.

Later, his much younger brother, the water-phobic and peculiar Bill-Bob, makes his debut, as does a wise Warm Springs Indian, Thomas Bigeater, who watches Celilo Falls on the Columbia River, where the Indians fish for chinook, get swallowed by the pool behind The Dalles Dam.

Gus grows up, “being educated by H2O and “gittin’ brung up” by Ma, to become a fishing prodigy. Upon graduation from high school, he ventures out on his own, renting a secluded cabin along the Tamanawis River in the Northwest Oregon Coast Range. His mission is to fish fanatically, on the “ideal schedule,” every day, sunup to sundown, to know fish better than most people know their own navels.

“I was free. I was alone. It was hell,” he reports.

Along the way, however, the chance encounter with a fisherman’s corpse floating in the river awakens him to the importance of expanding beyond his singleminded watery pursuits. He makes friends with his equally peculiar neighbors and finds mentors to guide his path.

Other unforgettable characters enter stage right. The self-made philosopher Titus and his dog, Descartes, teach Gus life lessons as they talk over tea.

“We were getting tired and a little giddy, and words like ‘pizza’ and ‘beer’ were beginning to sound better than words like ‘beatific’ and ‘immortal,’” Gus recalls.

Gus also gets out of his piscatorial cocoon and meets strange and lovable neighbors — hippies, dairy farmers and their abundant offspring — that populate the remote Tamanawis Valley.

Deeper truths and even deeper digressions abound in this bizarre tale. Gus returns to the suburbs to explore the highly polluted U.S. Grant Creek, the stream he most frequented as a youth, the one Indians called Sisisicu. What he finds is disturbing. He follows the steam searching for its headwaters, which turns out to be the second story of a three-story Benjamin Franklin bank under a mock Liberty Bell.

Then Gus follows the stream nine miles — under busy highways and parking lots and through backyards, “scunge, car bodies, garbage, sewage and shredded plastic” — before it dumps unceremoniously into the Willamette River. Some 300 yards from the mouth, he finds a pool with a living fish. He dangles an ant to catch perhaps the last trout living in the creek and transports it in a water-filled milk jug to the river for release and freedom.

Gus then goes back to the Coast Range cabin. He tries to find himself, in the way of an Indian boy’s vision quest to become a man. Gus hikes 50 miles up the Tamanawis River to its origins high in the mountains at a spring in search of his own “spirit-helper.”

The special place turns out not to be the headwaters but inside himself.

“A mecca isn’t worth much,” Gus decides, “if it’s not a place inside you more than a place in the world.”

A playful romance ensues when Gus, exploring another river system in the Coast Range, meets Eddy, whose style of fishing is as different from his own as Ma’s is from H2O’s. Eddy fishes from a tree hanging over a pool, using a huge 14-foot hazelnut sucker as a pole. The first encounter between the pair is a disaster. She disappears. Gus wonders if they’ll ever meet again.

Then Gus stumbles onto comically inept newspaper columnist Dutch Hines, “The Fishing Dutchman,” who Gus helps catch a fish or two despite Hines’ efforts to sabotage the operation. Gus agrees to be the subject of a column if the columnist puts in an obtuse paragraph meant to catch Eddy’s eye.

Sure enough, it works, and after much time apart, the couple gets back together and falls in love.

A master storyteller, Duncan unleashes these spirited characters like fireworks on the Fourth of July. With help from 5-year-old munchkins to aging philosophers, Gus finds a home for his adventurous heart and contentment amidst the turbulence of the times.

“The River Why” is a playful gem. Sometimes it wanders wildly in the metaphysical mountain ranges of the soul. But always it comes back to the oddball troupe of people that help Gus find his life’s true meaning.

A master storyteller, Duncan unleashes these spirited characters like fireworks on the Fourth of July. With help from 5-year-old munchkins to aging philosophers, Gus finds a home for his adventurous heart and contentment amidst the turbulence of the times.