Gloria dreams of adventure. She has led a quiet and monotonous life with Mathieu for seven years. She does not know orgasm and is frustrated by a restricted sexuality and by her desire for new experiences. Torn between the lightness of a dreamed life and the heaviness of a standardized life, Gloria undergoes this duality. Her companion Mathieu is locked in his selfish love. Frightened by Gloria's exuberance, he tries to curb his desires to the point of tearing himself apart. On her way, Gloria will meet Marion, a sex psychologist, who will push her to live sex as a catharsis. Marion, in love with Jessica, a young director, will also take a twisted path. While Jessica, frivolous and a sentimental, will only be in love with freedom. Her flippancy will be put in danger when she falls under the spell of her muse Gloria. Thanks to her relationship with Marion and Jessica, Gloria will go on a quest to search for her sexual identity and her freedom. What experiences will she choose to live? Will Mathieu accompany her in her quest? What outcome will Gloria will she choose to accomplish as a woman? This patchwork of love will try to answer these questions to find in the end only "the unbearable lightness of being".