YOU COULD describe "The Adventures of Sebastian Cole" as a coming-of-age story, but it's so much more charismatic than that.

"Adventures," a series of scattered, quirky episodes in the life of 17-year-old Sebastian Cole (Adrian Grenier), a disaffected youth living in a small town during the 1980s, is the artistic equivalent of supply-side economics.

Writer-director Tod Williams concentrates purely on generating a wealth of character. The heck with any narrative structural problems or unresolved subplots incurred along the way.

Handsome, listless, enigmatic Sebastian lives with his sister, mother and stepfather. Hank (Clark Gregg), his stepfather, has just finished chastising Adrian for poor conduct at school when he makes a rather shattering announcement. He intends to have a transgender operation. After which, Hank will become . . . Henrietta.

The family doesn't take this personal makeover too well. Mom (Margaret Colin), a kooky Brit, leaves immediately for England, taking Sebastian with her. And the sister (Marni Lustig) hops on the back of her boyfriend's motorbike and heads to California.

But after an unsatisfactory sojourn in England, Sebastian returns home to live with Henrietta, who wears dresses, doesn't try to modulate her voice and likes her cowboy boots just fine.

What's Sebastian going to do with the rest of his life? At Henrietta's insistence, he tries to remain focused on school -- as well as he can muster. But his main dream -- he claims -- is to become a writer. Of course, before he gets down to all that hard, creative work, he intends to live life to the fullest, just like Ernest Hemingway.

Sebastian doesn't chase game or marlin, but he does follow his impulses at every turn.

For starters, he begins a hot affair with local girl Mary (Aleksa Palladino). She's the one that kissed him one mysterious night before he left for England, and he remembers the flavor of that strawberry lip gloss. During their first date, at a movie, Mary asks him to pass her a sour-gum candy, but only after he has sucked off the sour part. She also wants him to pass it along with his mouth.

After a torrid, quick affair with Mary, Sebastian moves on with his life. He leaves Mary without explanation. It's cruel, but he's young, male and irrepressible.

He lurches into each new experience without restraint, whether he's buying a secondhand motorbike or walking into a drug dealer's motel room to ask him to forgive a junkie's debt or almost drinking himself to death one night. In these "adventures," Sebastian feels answerable to nobody except possibly Henrietta, who tries to keep him from being expelled from school. And there's something about his willful innocence and adventurousness -- both such essential parts of his nature -- that seems to protect, even ennoble him.

Will Sebastian straighten up, grow up, "learn" from all this? Filmmaker Williams, who claims that the Jim-Huck partnership in Mark Twain's "The Adventures of Huckleberry Finn" inspired the relationship between societal outsiders Sebastian and Henrietta, clearly wasn't compelled to create a triumphant "character arc" for our benefit. He concentrates purely on creating Sebastian's world. This unique approach and newcomer Grenier's breakout performance make "Adventures" seem directly plugged in to Sebastian's brain. You can almost feel the electronic crackles of his random urges.

As Hank/Henrietta, Gregg creates great character counterpoint. Instead of playing the transsexual role for "La Cage Aux Folles" laughs, or oozy poignancy, he goes for it head-on. So when the humor does arise, it does so naturally. When a local redneck showers Henrietta with predictable taunts, Sebastian's new stepmother gives the guy a beating that leaves him dazed.

"You kicked that guy's [expletive]," gushes Sebastian.

"Broke a nail," complains Henrietta as she struts away in those cowboy boots.

THE ADVENTURES OF SEBASTIAN COLE (R, 99 minutes) -- Contains alternative sexuality issues, drug taking, sex and nudity. Cineplex Odeon Dupont Circle.