Lily is a sheltered art student from Michigan attending college in California. She finds an apartment, and she soon notices her roommates, Tanya (a friendly lesbian artist who becomes a good friend to Lily), Bridgette (a cruel and taunting artist who initially takes an immediate dislike to her), and Robert (the silent but talented musician), all art students, aren't quite normal. For the first time out of her village, she is still used to her protected life in Michigan and frequently calls her parents. One day she discovers a box of items belonging to Ivy, a girl she has never met before. In the box, she finds nude pictures of the girl and her diary. She is soon drawn to the content, also desiring for the girl's sexual confidence and fearlessness. In class, she has trouble expressing herself, unlike Gredin, an attractive co-student and sculptor she soon starts dating. Meanwhile, she has found a job, babysitting Daphna, the daughter of her art teacher Donald Falk.

Slowly, one step at a time, Lily becomes obsessed with Ivy's letters and photos, attempting to take over her image. Soon enough, she cuts her hair, pierces her belly button and starts wearing more revealing clothes. Gredin grows even more attracted to her and it doesn't take long before they start having sex. He is unamused by the amount of private time she spends with Donald, though, but she explains it's because of the babysitting. She inspires Donald to perform art again, having noticed that he's long been afraid to express himself. She agrees to pose nude for him, and also finds her own way to express herself in the meantime as well. During this process, he secretly falls in love with her, which has a great deal of impact on his marriage to Angela. However through the movie, it can be shown that Donald's infatuation with her soon deepens to obsession.

One day, Lily catches Gredin and Bridgette together. Feeling upset, she starts to rebel, thereby estranging herself from her friends. At a party, she enjoys the attention she is getting from men, and she amuses herself, until she sees Gredin intimately dancing with another girl. Trying to make him jealous, she kisses a masked guy, who turns out to be Robert. She eventually spends the night with Gredin, but he dumps her the next day, explaining she has changed too much. Meanwhile, Angela has found Donald's drawing of Lily and thinks he has an affair with her. Donald, already depressed since he saw Lily kissing Gredin, takes it out on Lily. He later claims he is in love with her and tries to kiss her. She is initially unamused by his attempts, but they eventually heavily make out with each other, until they are interrupted. She leaves and soon reunited with Gredin.

Not much later, she is invited for dinner at the Falk family and brings Gredin with her, which upsets Donald. When they are alone in a room, Donald forces himself upon Lily. She tries to stop him, but has no success. They are eventually caught in the act by Daphna, who runs away and is hit by a car (but luckily, in Gredin's words, ends up "going to be all right"). Lily, traumatized by what happened that night, returns home and destroys everything that has to do with Ivy. She is surprised by a psychotic Donald, who attacks her. Gredin tries to save her, but Donald beats him up and even tries to stab him. She tries to run away by going to the roof. He follows her and eventually falls off the roof to his death. In the end, Lily and Gredin say they love each other, and they finally decide to be with each other.

女主从很远的地方到城里求学艺术，与她共住的小伙子互生情愫。在学习中，教授对这个女孩特别青睐，甚至在辅导过程中故意做出亲昵动作。这让女孩共住的男孩很不爽，甚至说出了伤害女孩的话，把女孩气走了。男孩主动向女孩承认错误，并表达了追求之意，女孩不但原谅了男孩，还和他打得火热。这时女孩找到了工作，就是去教授的家里帮着带教授女儿，这样也给了不少教授接近女孩的机会，这让与女孩共住男孩的不满。男主甚至用与其他女孩交好的方式，让女孩难受。但是女主从自己房间发现了一个女人的日记，她模仿着日记里的女子的模样，改变着自己的形象，甚至从一个淑女变为了一个放荡不羁的女子，就是为了体验日记里的生活。渐渐的，她还利用与教授讨教艺术的机会，几乎与教授发生不伦恋，幸亏教授的另一个情人来访才停止了不伦关系，这也让女主警醒，不再多于教授来往。但是越是这样，教授越是激情难耐，但是限于女主的男友在身边，不敢造次。一次，教授的妻子邀请女主与男友到家中吃饭，教授利用照顾女儿为由，让女主陪他上楼，利用这个间歇，想强奸女主，但是教授女儿出现，让教授没有得逞。车辆撞倒女儿，教授竟然不顾一切，继续前去追赶女主，最后在争执间，跌下楼摔死了。女主与男友重归于好……

影片有些为了激情而激情，这样就弱化了情节。如果将女孩因为日记的转变再彻底一切，迷失地在曲折一些，让她与教授的爱意更有说服力一点，也许这部影片会有更好的情节。另外那个拉大提琴的亚裔模样的男子好像也对女主有好感，但是影片弱化了他，几乎没有出来几回。他与这个箱子的主人有关联嘛？还有女主大男友与这个箱子有关联嘛？为什么留下箱子，好多事都没有交代清楚，但是一不留神就激情戏，减弱了这一切。

不过女主颜值身材都在线，还是很养眼的。恬静的时候恬静，清纯时也可以清纯，但是野性起来也是很难hou得住，千面佳人，一级棒……