This fact-based, girl-group empowerment story never quite soars, but has its easy pleasures, and it’s likely to become one of those movies everyone sees, maybe more than once. The wonderful Irish actor Chris O’Dowd, who played the laid-back highway patrolman in Bridesmaids (2011), stars as Dave Lovelace, a musician living out of his car who stumbles upon a gifted girl group in rural Australia circa 1968. The four young women are Aboriginals, and as such are shunned and abused by white neighbors they’ve known all their lives. When Julie (Jessica Mauboy), the one with the really great voice, sees an advertisement seeking acts to perform for American troops in Vietnam, she convinces the others (Deborah Mailman, Shari Sebbens, and Miranda Tapsell) to audition. After Dave encourages the girls to switch their repertoire from Merle Haggard to Otis Redding tunes, the girls soon find themselves performing in Saigon and the war zone beyond. First-time director Wayne Blair and screenwriters Keith Thompson and Tony Briggs, adapting Briggs’ stage play, don’t shy away from the era’s social complexities, but they keep their eye on the ball, which in this case is the sweet pull of soul tune harmony. Why resist?