Dissatisfied with his life, Winston reasons that it is the Party's fault. He starts to seek out ways to rebel against the Party, first by starting a journal, then by starting an affair with Julia.
Something big is missing in Winston Smith's life; he sets out to find fulfillment by engaging in rebellious acts.
O'Brien approaches Winston in the corridor at work, and inducts him and Julia into a revolutionary group called the Brotherhood.
Winston becomes more and more absorbed in acts of subversion, and for a while here, things are going so improbably well that he thinks he and Julia might escape the Party.
Winston reads Goldstein's Manifesto, but fails to grasp the reason or the "why" underlying the resistance.
Winston is frustrated that he can't seem to find the "cream" to the Manifesto. In his words, he understands the how of the rebellion, but he doesn't understand the why.
At the height of their love and bonding, Winston and Julia get caught by the Thought Police and sent to the Ministry of Love for prolonged torture, interrogation, and brainwashing. Finally, he is forced to face his ultimate fear in Room 101.
Just when things can't get any better, they get worse. Winston gets caught. With his pants down. It is very abrupt, and it is a total nightmare.
Upon release from the Ministry of Love, Winston is reintegrated in society, now merely a shell of a man. Winston essentially "retires" at the Chestnut Tree Café, living his life only to be shot to death (though we never see this).
Having finally escaped the many nightmares leading up to his worst nightmare, Winston is now content. In fact, he believes he is genuinely happy because he has learned how to be ignorant and unquestioning. But in fact, he is in a daze...and there is every implication that he will be shot by the Party in the near future. Not that he minds, really.