At the beginning of the novel, Anastasia Steele is an innocent Washington State University student with romantic ideals and dreams of working in publishing. By a chance coincidence, she meets Christian Grey, a wealthy Seattle businessman. Although notoriously private and reclusive, Christian begins to show interest in learning more about Ana. Initially, Ana is slightly repulsed by Christian's cold and domineering attitude, but she cannot deny her attraction to his good looks and confidence. Christian woos Ana with expensive gifts, but also begins to show controlling tendencies. When Ana makes her feelings clear, Christian initially tells her that the two of them are not compatible. A short time later, however, he admits that he is deeply attracted to her.
After confessing his desire, Christian reveals his secret to Ana: he does not engage in traditional romantic relationships, and has no desire to fall in love with someone. He achieves sexual gratification by engaging in dominant-submissive relationships where a woman agrees to be submissive in all aspects of her life, and accepts physical punishment when she violates any aspect of their contract. Christian also likes to engage in acts of bondage, domination, and sadism. Ana is astonished and overwhelmed by what he discloses, especially because she has never had a sexual relationship of any kind. When she confesses this to Christian, he decides to begin with "vanilla" (non-dominant) sex first, and the two of them begin a sexual relationship.
Christian and Ana have explosive sexual chemistry, and the pleasure Ana experiences makes her curious about exploring the relationship further. However, she inherently dislikes the idea of having to submit to Christian and potentially experience humiliation and physical punishment. She is also hurt by Christian's refusal to consider any form of emotional intimacy. Over the next few weeks, Ana and Christian have an undefined relationship that challenges both of their boundaries and expectations. Christian continues to hope that Ana will sign the contract and become his submissive, but he also becomes more attached to her, and more open to experimenting with some elements of emotional intimacy. As he opens up, Christian reveals hints of an unhappy childhood before he was adopted. He was initiated into BDSM as a teenager by an older woman. He is still in contact with this woman, which ignites Ana's jealousy.
Ana is torn between her desire and increasing tenderness for Christian, and her fear that they want different things. Ana is confused by her response to the kinky sexual practices Christian introduces: she often experiences pleasure, but she is also left feeling ashamed and afraid. She dislikes when Christian behaves in overtly controlling ways and interferes in her life. More importantly, she is hurt by Christian's unwillingness to be truly vulnerable and open with her. Ana is at a crucial juncture in her life, having just graduated college and preparing to begin an internship at a publishing house. She is frustrated by how much of her life is becoming centered on her relationship with Christian.
In an attempt to better understand Christian, and to fully know what she is agreeing to, Ana asks Christian to do the worst he can to her. He strikes her repeatedly with a belt, leaving her humiliated and furious. Ana decides that she and Christian can never be together, since he can't live without physical dominance, and she is unwilling to tolerate it. Although it breaks her heart, Ana ends the relationship with Christian.