Even though he had been half expecting it, the message from O’Brien when it finally came was a shock to Winston. O’Brien stopped him quite openly in the corridor and started a conversation about Newspeak. He introduced what Winston recognized as a coded reference to Syme in the talk and by this open flaunting of the thoughtcrime of referring to an “unperson” Winston felt that he and O’Brien had somehow become accomplices in a plot.
In full view of a telescreen, O’Brien wrote down his address and gave it to Winston with an invitation to come over and look at the latest edition of the Newspeak dictionary. The very daring of the act convinces Winston that there must be something behind the invitation- that perhaps the fabled brotherhood did exist and he was finally being invited to join.
Winston was thrilled and terrified at the same time. He knew that sooner or later he would follow up on O’Brien’s invitation. But at the same time he felt certain that he was embarking on something which would have its ending behind the dread walls of the Ministry of Love. And yet, he could in no way desist from responding. Winston routinely destroys the piece of paper on which O’Brien had written the address, but he memorizes it beforehand and the invitation haunts him constantly with an equal measure of terror and fascination.