It's the 1970s, and from hippie London to Warhol's Factory in New York, reluctant aristocrat Loulou de la Falaise is desperately seeking adventure. Having escaped an early, unhappy marriage, she arrives on a whim in Paris—the champagne-soaked heart of the fashion world, where the rigid old world of haute couture and the fast-paced new world of ready-to-wear are vying for supremacy. Glamour, sex, and cocaine nights fuel the Paris fashion scene. Its crown prince is the soulful and intensely gifted Yves Saint Laurent, whose sexy tuxedos for women and chic Rive Gauche boutiques reflect women's desire for seductive independence, a desire Loulou knows all too well.
 
Loulou's bohemian flair immediately captures Saint Laurent's attention, and they embark on a glorious intimate friendship as artist and muse. Together they revel in the excesses of high society, decadent parties, and the hedonistic underworld of gay nightclubs, where the young and beautiful become prey, and dangerous rivalries start to emerge. Their course collides with eccentric designer Karl Lagerfeld, intent on his own conquest. Lagerfeld's bitter professional rivalry with Yves divides Paris even in an era when anything goes. As Yves plunges into a dangerous, secret affair with Karl's enigmatic young companion, and Loulou finds herself falling in love with a colleague's handsome boyfriend, evanescent illusion and savage deception will bring them to the brink of ruin.
 
Intoxicating and unforgettable, The Saint Laurent Muse is the dramatic story of a lifelong friendship between two kindred spirits, and of a tumultuous time and place in fashion history that will never be seen again.