An earthy Kathleen Turner almost raises High

Kathleen Turner and Evan Jonigkeit in "High"

In his 1940 novel The Power and the Glory, Graham Greene introduced us to the "whisky priest." Now Kathleen Turner brings to raucous life the female counterpart: the whisky nun.

In High, the flimsy play she's headlining at the Royal Alexandra Theatre, Turner is a hoot as Sister Jamison Connolly, a hard-boiled addiction counsellor who knows whereof she speaks. Sister Jamie may be clean and sober now, but in her wilderness years she had an unholy thirst for Jack Daniel's. When times got tough, however, rubbing alcohol would do, or even that old rummy's standby, vanilla extract.

This plain-clothes sister has also spent her time down among the sinners and has the street smarts and four-letter vocabulary to prove it. When she swears – which is frequently – it's in that familiar throaty, bourbon-and-cigarettes voice that has only gotten deeper and raspier as Turner has aged.

Sister Jamie is a role tailor-made for the 57-year-old movie star – one much closer to her ballsy characters in Body Heat and The War of the Roses than to her strait-laced Catholic mom in The Virgin Suicides. And Turner clearly relishes every flip retort and F-bomb. Her earthy performance is the only reason to see this stale tale of addiction and redemption.

But you don't need me to tell to you that. The New York critics said as much last spring, when High opened on Broadway only to close after eight performances. Undaunted, its producers remounted it early this year for a tour that includes the current brief engagement at the Royal Alex (David Mirvish was one of the backers of the Broadway show). The playwright, Matthew Lombardo, has apparently done some rewrites, but that isn't enough to raise the script above the level of an overheated TV melodrama.

The story concerns Sister Jamie's efforts to treat Cody (Evan Jonigkeit), a gay teenage meth addict who was found drugged up next to the dead body of a younger boy. Sister Jamie has taken the case reluctantly – at the insistence of her superior, Father Michael (Tim Altmeyer) – and she has no patience for Cody's surly-teen attitude or classic addict behaviour. As she metes out her brand of tough love, the kid begins to open up, revealing a nightmarish childhood that included helping to shoot up his prostitute mother with heroin and enduring sexual abuse from her supplier.

That's just the beginning of an onslaught of revelations, from Father Michael's secret connection to Cody, to the horrific trauma in Sister Jamie's own past. There are so many plot twists that by the time we finally learn what really happened between Cody and the dead boy, it feels anticlimactic.

Lombardo is both a Catholic and a recovering meth addict and the play is a sincere advertisement for faith-based treatment. But he's also addicted to sensationalism, as if he had to convince us of just how ugly and sordid the drug world can be. When seamy descriptions aren't enough, he throws in a scene where a doped-up Cody strips naked and attacks Sister Jamie – an episode clumsily and unconvincingly staged by director Rob Ruggiero.

On the other hand, Lombardo is also known for writing vehicles for famous older actresses – his previous Broadway effort, 2010's Looped, starred Valerie Harper as Tallulah Bankhead. In that respect, he skillfully plays to Turner's strengths. The play's glib early scenes allow her to show off her crisp comic timing, as she spars verbally with Jonigkeit and Altmeyer and inevitably lands the knockout punchline. She also gets to deliver a series of soul-baring monologues to the audience, in which her salty nun recalls her preconvent life and wrestles with her moral weaknesses between wisecracks.

Jonigkeit, repeating the role he played on Broadway, is a striking physical presence as Cody. His eyes deep-set, his hair in a permanent state of bed-head, he paces about David Gallo's minimal set looking wiry and agitated. He's almost a cartoon of the drug-deprived addict. It's an impressive but superficial performance. Altmeyer, in contrast, brings some authentic feeling to the part of the pedantic priest whose smugness masks a private pain.

Turner herself is never entirely convincing, but that may have less to do with her acting than with our knowledge that we're watching a star turn. After winning accolades onstage in the work of Edward Albee and Tennessee Williams, it feels like this time Turner has gone slumming. But at least she has one helluva time doing it.

High runs until May 13.

High