Though the boys have intended to remain true to the Lisbon girls, they are troubled that their memories and experiences of the sisters are slipping away as the spring progresses. A year after Cecilia's death, the boys still do not know why she committed suicide, nor the sisters' true feelings about the suicide. The boys begin to wonder if they had ever really known the Lisbon sisters. Just as the boys feel they have lost the girls entirely, secret messages begin appearing. Plastic cards of the Virgin Mary are left in bushes or between bicycle spokes. At night, Lux's Chinese lantern blinks an indecipherable code, and the flames of candles are visible in Cecilia's old room. On May 7, neighborhood boy Chase Buell finds a note in his mailbox instructing the recipient to tell Trip that he is a creep and that "Guess Who" is over him. In the next few weeks, various notes arrive, though the boys are never able to catch the girls delivering them. Unable to devise a suitable means of reply, the boys finally decide to use the telephone.
The first call is answered by Mr. Lisbon. The boys remain silent until Mr. Lisbon hangs up, after which a tentative girl's voice says hello before hurriedly hanging up. The next day, at the same time, the boys' call is answered on the first ring. Without speaking, the boys play a song into the phone, give their phone number, and hang up. The following day, same time, the boys' phone rings. The boys answer immediately and hear a song playing. At song's end, the boys play a song back, and the game continues for much of the evening. Years later, the boys will not be able to remember the exact songs played, only that the exchange suggests a kind of seduction, as the boys play love songs while the girls demurely play folk songs in reply. Finally, in a burst of intimacy, the girls play David Gates' "Make It With You," and the line goes dead.
Thrilled and barely able to believe that the girls might like them back, the boys continually try to call the Lisbon house again, but no one answers. Three days later, they observe the girls packing trunks, and presume that they are plotting an escape. On June 14, a note appears in the boys' mailbox scrawled on a plastic picture of the Virgin Mary: "Tomorrow. Midnight. Wait for our signal."
On the night of June 15, each boy tells his parents that he is sleeping over at someone else's house, and the boys climb into their childhood treehouse to drink and wait. Midnight passes, and some time later, a flashlight blinks three times in the Lisbons' window. Almost as one, the boys descend and make their way to the Lisbon house.
Through the back window, the boys see Lux sprawled alone in a beanbag chair in a halter-top smoking a cigarette. Disarmed by her presence, they quietly open the door and enter. Lux appears to have been expecting them. The boys tell Lux that they have a car and a full tank of gas and promise to take the girls anywhere they want. Lux claims her sisters are not quite finished packing, as it has taken her parents forever to fall asleep. The boys beg her to hurry. Lux stands up, walks over to Chase Buell, and unbuckles his belt. The room is silent and every boy imagines that Lux is unbuckling his own belt. Hearing a soft thud from downstairs, Lux stops and decides that time is of the essence. She tells the boys to wait in the living room for her sisters while she waits in the car. The boys do as they are instructed, and dream of their flight with the girls.
Perhaps twenty minutes later, aware of the house's complete silence and noticing a light coming from the basement, the boys decide to venture downstairs. As they enter the basement, they see the punch bowl from the Lisbons' party still half- full and covered with scum, and an inch of floodwater covering the floor. One boy wades out and begins to dance. Behind him, the others catch sight of Bonnie, in a pink dress and confirmation stockings, hanging dead from a beam. As they watch in horror, her body begins to slowly twist. The boys flee, silently, and forget to check the garage for Lux. Later, they will learn that Bonnie probably died while they sat in the living room, that Therese was dead by sleeping pills before they entered the house, and that in their dark path to the basement they narrowly missed Mary with her head in the oven. Meanwhile, Lux's death by carbon monoxide poisoning must have occurred shortly after the boys' departure. The boys realize how cleverly Lux stalled them, giving herself and her sisters time to die in peace.