To someone new to Washington State, Key City Public Theatre’s premiere of the new musical, Wild Man of the Wynoochee, might conceivably sound like an invitation to an all-singing/all-dancing spoof on the old West. Instead, the show, with music and lyrics by Linda Dowdell and book and lyrics by Jessica Welsh, recounts the true tale of killer John Tornow (Casey Raiha), who spent two years in the early 20th Century eluding capture in the Wynoochee Valley of southern Grays Harbor County.

Sensationally dubbed “The Cougar Man,” “A Mad Daniel Boone,” and “The Wild Man of the Wynoochee” by the regional press, the longtime nature-loving recluse was eventually killed by bounty hunters in the spring of 1913. The spectacle that ensued, with a mob of 250 people storming the morgue where his remains lay and 650 people gazing at his lifeless body in a span of 30 minutes, thankfully plays no part in the musical.

Instead, Welsh and Dowdell view Tornow through exceedingly sympathetic eyes. Without visiting the first part of his life — Tornow began vanishing into the woods for weeks at a time when he was 10 years old, and was eventually incarcerated in a mental institution by his two brothers for almost 12 months until he could escape — they sing their way through the tale of an extremely sensitive, loving, and determined man who is easily pushed over the edge into violence.

John Tornow’s brothers are compacted into one, the evil Ted Tornow (Robert Winstead), who capitalizes on misfortune to hunt down John and inherit his money and land. Throw in a sensitive and deeply understanding newfound girlfriend, Amanda (Anna Mae); a vacillating but concerned sister (Christa Holbrook); a sympathetic but ultimately forced-to-pursue Deputy Sheriff (Ricky Spaulding); one of the more sensationalizing and self-absorbed yellow journalists ever to inhabit the human body (Bry Kifolo); and a caught-in-the-sights and eventually murdered 19-year-old nephew, Will Bauer (Angel Vargas), and you end up with a nine-person show.

The longish first act of the musical is surprising compelling. Dowdell’s 26 tunes are hardly memorable — replacing a few numbers with a bit more dialogue would improve the tale’s unfolding — but they effectively tell the story and move the action along. The songs also give the best singer in the cast, Holbrook, ample opportunity to display her impressive versatility and range.

The unseen director, Brendan Chambers, manages to make Key City’s stage seem far larger than it is. Be it during dialogue — there’s far less of it than one might think — or song, Chambers’ approach is consistently imaginative and expansive, ensuring that the eye and senses remain curious and engaged.

Only in the shorter second act does the musical falter. An incongruous infusion of Silver Screen sentimentality cheapens the story, with a gratuitously sunny finale that seems disconnected from all that preceded it. It would have been far better to have amplified the feelings that make the first part of the show so meaningful.

What stays with you after the show’s conclusion is how well Artistic Director Denise Winter chose her talented and immensely capable cast, how much of themselves each actor puts into their role, and how trapped and tragic a figure John Tornow may have been. Raiha, Winstead, Holbrook, and Kifolo play their characters for all they’re worth — Raiha is outstanding — and Spaulding, Mae, and Vargas are close behind. Musical director and keyboardist Linda Dowdell beautifully manages her partially visible band of six, and every other member of the creative team does their exceedingly professional part.

Only one quibble amidst the goodness: As much as Taylor Thomas Marsh’s vocal enhancement remains a lamentable necessity in our aging community, more work needs be done to soften the bright electronic edge it puts on voices. The annoyance is minor, however, and hardly detracts from the show’s overall excellence.

Wild Man of the Wynoochee runs Thursday through Sunday until Oct. 27. The Oct. 13 performance is ESL-interpreted, and free AfterWords events with the artists follow the Thursday evening and Sunday matinee performances.