This long-lost masterpiece of hardcore gay erotic cinema centers on a handsome young stud who rides his motorcycle through myriad sexual encounters, from a soccer game’s locker room to a phantasmagoric and deeply melancholy orgy. A labyrinth of all-male fantasies whose outstanding beauties always end up fading away while leaving their sensual protagonist dealing with his own loneliness, EQUATION was directed with supreme grace by the mysterious Dietrich de Velsa (aka Francis Savel/Frantz Salieri). A former painter, de Velsa was also the owner and artistic director of La Grande Eugène, one of the first drag cabarets in Paris. Years later, he collaborated with Joseph Losey on MR. KLEIN (1976) and DON GIOVANNI (1979). His one and only film, EQUATION TO AN UNKNOWN stands as one of the most extraordinary erotic films of all time.
　　“The most melancholic porn film I’ve ever seen. It’s very sad, and aesthetically beautiful. Just a young man wandering through several depictions of love and choreographies of love-making; it’s like a ceremony, a ceremony of fantasies, especially the last sequence where the main character recalls all his previous fantasies, which come one by one around his bed and make love to him. I think it’s one of the most beautiful film sequences of French cinema.” –Yann Gonzalez

　　即将入职的内阁部长史蒂夫（杰瑞米•艾恩斯 Jeremy Irons 饰）同妻子英格丽、儿子马丁（拉珀特•格雷夫斯 Rupert Graves 饰）平静安逸地生活着。安娜（朱丽叶•比诺什 Juliette Binoche 饰）的出现像是一股汹涌的暗流冲撞着这个看似完满的家庭。安娜是儿子的女朋友，却背地里与史蒂夫展开了一段热烈浪漫的关系。安娜曾经在青春期里与哥哥的畸恋记忆一直影响着她，这使她一面寻找各种机会和史蒂夫约会，一面又能泰若自然的面对马丁，而当史蒂夫提出要抛弃家庭与她厮守时安娜却冷静地拒绝。某日马丁开门见到二人相会的情景，震惊和痛苦使他不慎跌下楼梯，史蒂夫匆忙下楼抱着死去的儿子，安娜此时却无声地离开，只留下身后中年男人无法重建的坍塌生活。

一个大雪纷飞的寒冷夜晚，学者赛里格曼（斯特兰·斯卡斯加德 Stellan Skarsgård 饰）偶遇了遍体鳞伤躺在雪地里的女子乔伊（夏洛特·甘斯布 Charlotte Gainsbourg 饰），好心的赛里格曼将乔伊接回家里疗养，却没想到，等待着他的，会是一个充满了扭 曲情欲的故事。                                                                      　　影片随着乔伊的讲述徐徐展开，年纪很小的时候，乔伊（斯黛茜·马汀 Stacy Martin 饰）就发现了自己拥有异于常人的高涨性欲，年幼的无知和懵懂让乔伊欣然接受了自己的不同，随着年龄的增长，她开始大胆又奔放的徜徉在情欲之海中，甚至和好友一起创办了专门接纳“女性瘾者”的俱乐部。乔伊的第一个男人名叫杰罗姆（希亚·拉博夫 Shia LaBeouf 饰），当成年后的乔伊再度遇见杰罗姆之时，她发现自己竟然深深地爱上了他，而悲剧的是，乔伊发现，唯独杰罗姆的爱抚无法燃起她的激情，在性和爱之间，乔伊陷入了深深的迷惘之中。