Ten years. Five women. One concert. Your reunion was never this good. Or this complicated.

A decade ago, Callie Smalls made a daring exit from her chart-topping all-girl music group to chase her dreams in fashion and television, leaving her bandmates behind. Now, after hosting a hit reality show, she's desperate to reignite her career and decides on a risky move: staging a one-night-only reunion concert without consulting her former friends.

But the Sassy Cats aren't the same girls they used to be. Scattered across the country, each faces unique challenges: a soccer mom hiding her past from her husband, a fading star clinging to the spotlight, a party girl confronting unexpected responsibilities, a tiger mom fighting for her son, and a woman trapped in unhappiness and isolation.

As tensions simmer and old wounds reopen, will they rediscover the magic that once bound them together? Or will resentment and discord drown out their harmonies for good? A tale of friendship, ambition, and the power of music, Once in a Lifetime explores the intricate dance between love and betrayal in the pursuit of fame.