“What am I doing here?” asks the magnificent dancer Tony Yazbeck portraying legendary movie star Cary Grant as he is about to experiment with LSD with two other luminaries—controversial novelist Aldous Huxley and playwright-diplomat Clare Boothe Luce—in the physically ravishing but emotionally numb new musical Flying Over Sunset (at Lincoln Center’s cavernous Vivian Beaumont Theater). I felt a similar unease and uncertainty at this lush concoction from an impressive creative team. The book and direction are by James Lapine who collaborated with Stephen Sondheim on three of his most innovate pieces—Sunday in the Park with George, Into the Woods and Passion. The score is by composer Tom Kitt (Next to Normal, music arranger/supervisor for Jagged Little Pill) and lyricist Michael Korie (Grey Gardens, War Paint). The songs are sweet, the orchestrations by Michael Starobin are smooth as silk, the sets, costumes and lighting are gorgeous. But something vital is missing—an emotional center, a reason to care whether or not this diverse trio will take the drug and about what they discover on their trip.

The central idea is intriguing, yet Lapine and company fail to make it compelling. Grant, Huxley and Luce all tried LSD in the 1950s when it was legal. Lapine’s book imagines a meeting of the three along with writer-philosopher Gerald Heard who later acts as a drug “guide,” at the Brown Derby restaurant in Hollywood. This is preceded by the separate stories of Grant, Huxley and Luce and what motivates them to expand their consciousness.

It’s not clear what Cary Grant’s dilemma is—there is vague dialogue about his failure to commit to any of his three wives (there would be a fourth later). Lapine plays coy with the star’s alleged bisexuality and only briefly mentions the fact that he shared “bachelor quarters” with Randolph Scott for nearly 12 years. Huxley is seeking enlightenment for intellectual reasons. That is until his wife dies of breast cancer and then his incentive for drugging is to deal with his grief. Luce has a similar backstory as she turns down a diplomatic appointment by the Eisenhower administration while struggling with the death of both her mother and daughter in separate auto accidents.

In the second act, they gather at Luce’s rented Malibu beach house and have psychedelic breakthroughs while Beowulf Borrit’s versatile sets transform into dreamscapes with the aide of Bradley King’s hypnotic lighting and enchanting video projections by 59 Productions. (Toni-Leslie James’ period costumes are spot on.) All hug each other at the end, having achieved a form of contentment via LSD. Along the way, the scenes veer wildly from smashingly entertaining (Grant tap dances with his cross-dressing younger self; a beautiful recreation of a Botticelli painting) to bizarre (Grant imagines he is a giant penis blasting off into space; Luce searches for her dead mother’s leg which was amputated in the car crash). The musical’s raison d’être is never brought into focus. Is Lapine saying drugs help with psychological problems? That the 1950s were a repressive decade? That famous people are just as mixed up as the rest of us? These themes battle for dominance and none win.

Luckily, the performances are solid and vibrant. As Grant, Yazbeck displays his considerable triple-threat skills, creating a complex, unhappy movie star and establishing himself as Broadway’s leading dancer. As his terpsichorean partners, Atticus Ware as the childhood Grant and Emily Pynenburg as his co-star Sophia Loren dazzle. Choreographer Michelle Dorrance supplied the eclectic routines.

Carmen Cusack’s rich vocals and compassionate limning bring Luce to life and Harry Hadden-Paton makes Huxley much more than a dry thinker. Robert Sella exposes the repressed yearnings of the celibate, homosexual Heard.

The evening is definitely a mixed bag. While the libretto is confusing and unfocused, many fascinating facts are disclosed. For instance, Grant’s wife Betsy Drake wrote a screenplay for the couple to act in, but it was transformed into Houseboat co-starring Loren as the female lead. Huxley defended a fired teacher for recommending his dystopian novel Brave New World to a student. Luce was a war correspondent and editor before turning to politics. Even more tidbits can be found in the handsome Lincoln Center Theater souvenir program book. But interesting bits of information do not a coherent musical make. When the program is more interesting than the show itself, something is wrong.

Dec. 13—Jan. 16, 2022. Lincoln Center Theater at the Vivian Beaumont Theater, 150 W. 65th St., NYC. Tue 7pm; Wed 2pm & 7pm; Thu 7pm; Fri 8pm; Sat 2pm & 8pm; Sun 3pm. (Check the website for schedule changes during holiday weeks.) Running time: two hours and 45 mins. including intermission. $59—$249. www.telecharge.com.