Happiness, that much-desired yet slippery state, becomes a contentious emotional concept in the New Theatre premiere of Robert Caisley’s provocative new play Happy.

A college professor claims to be quite happy with his life, despite challenges that include raising a 15-year-old daughter with cerebral palsy. A much-younger artist, the one-month-and-counting lover of the professor’s best friend, thinks the “freakishly happy” guy about whom she’s heard so much has to be a phony.

So over the course of 90 wild and intriguing minutes, she proceeds to break through his sustaining mental narrative and, in essence, emotionally disembowel him.

Happy is the third play by Caisley, after 2009’s Kissing and last February’s Winter, to get a New Theatre premiere – this one as a National New Play Network “rolling world premiere” in which four theaters agree to mount separate productions of a new play. Already seen in Montana and headed for theaters in New Jersey and California, Happy is getting a fine interpretation by New Theatre, one of the company’s best in several seasons.

Caisley’s script is funny, deliberately unnerving, full of smart dialogue and stinging rejoinders. Its central character is Alfred (Scott Douglas Wilson), a guy who teaches French literature, has been happily married for 14 years and adores his disabled daughter.

Alfred and his bubbly wife Melinda (Jessica Marion Welch) have been invited to dinner at the home and studio of Alfred’s best bud Eduardo (Ernesto Miyares), an artist and fellow professor. But the couple drives separately so Alfred arrives first, his pants soaked because of an SUV driver who appeared to deliberately steer into a huge puddle. Eduardo’s apartment door is open, so Alfred enters, dripping and bearing wine, only to be greeted by a shriek from Eduardo’s gal pal Eva (Maria Corina Ramirez), who’s wearing nothing but a turban, a towel and an attitude.

Though Eduardo and Melinda certainly figure into the play (and are engagingly portrayed by Miyares and Welch), the real contest here is between the self-professed “happy” man Alfred and the manipulative Eva, a seductive truth-twister who’s the age of one of Alfred’s students. Alfred enters the play as a buttoned-up, geeky guy who has sacrificed his youthful dreams for grown-up responsibility. He ends the evening bloodied, drunk, in his underwear and smoking as he stares at Eva, who has opened her robe to let him see her hidden tattoo. In Happy, there is but one victor, and it isn’t Alfred.

Director Ricky J. Martinez has cast and staged Happy unerringly, also contributing the production’s sleek set design (the key art on the walls is by Theresa Marie Callouri). Wilson, a busy actor who teaches at Miami’s New World School of the Arts, gives a warm, amusing, intense performance as a man pushed over an emotional edge. Ramirez, a young New World grad, creates a pathological manipulator who’s nonetheless tough to resist.

Caisley, who teaches playwriting at the University of Idaho, was in New Theatre’s audiences over his play’s opening weekend. He’ll doubtless learn things from each of the script’s four productions, but what Martinez, Wilson, Ramirez and company have created should send him home happy.