After examining Margo’s (Cara Delevingne) last clue a map of the U.S. at the abandoned souvenir shop with Ben (Austin Abrams), Marcus (Justice Smith), and Lacey (Halston Sage), Quentin (Nat Wolff) finds out that a trail she made on it ends in upstate New York in what looks like the middle of nowhere. After Marcus checks out the names of the towns in the general vicinity over the Internet on his phone, Quentin asks him if any of them are paper towns, and Marcus discovers on the Omnictionary website that Agloe is such a town, and a picture attached with the entry shows an abandoned barn. Also, a post underneath it says that the town’s population is now 1, and Quentin realizes that Margo posted that message and therefore must be there. Ben tells him that he needs to go there immediately, but when Quentin initially isn’t keen on going since it is a long way from Orlando, Ben says that he must make the journey because she is his true love. Quentin admits that he does love her, so he decides to go, and Ben, Marcus, and Lacey agree to join him. However, Marcus makes it clear that they need to get back in time for the prom, plus he has to make a stop first. They take him to the home of his girlfriend Angela (Jaz Sinclair), where he fills her in on the impromptu trip, and she decides to come along as well. However, she first manages to make Marcus admit that he is afraid to lose her, which is why he hasn’t let her in on certain aspects of his life that he is embarrassed about.
When they are forced to make a pit stop along the way, Lacey asks Ben to be her date to the prom after they had spent the last couple of days connecting, and Marcus and Angela renounce their decision to wait until the prom to consummate their relationship and have sex then and there. They get to the abandoned barn that marks Agloe, but a search of it and the surrounding land turns up nothing. After a short argument with the others about how they really want to get back in time for the prom and questioning if Margo will show up at all, Quentin flips them the keys to his van and tells them to head back to Orlando without him so he can wait a little longer, so they depart. After a while, Quentin accepts that Margo isn’t going to appear and hitches a ride to nearby Roscoe, where he purchases a ticket for a bus heading back home.
While in a store buying snacks for the journey, he spots Margo passing by and gets her attention. After hugging her, he gets confused after she says that she is surprised to see him. He then brings up the clues she left for him, and she informs him that those clues were just to let him know that she was okay and weren’t an invitation for him to follow her. He tells her he has been in love with her since they were kids, but she replies that he actually isn’t in love with her and doesn’t even know her, and she doesn’t know herself, either, which is why she is here. They sit and talk some more, where she explains that she had been wanting to leave Orlando for a while and had planned to go after graduation, but the departure date got moved up after she found out that her boyfriend Jason (Griffin Freeman) was sleeping with Rebecca (Caitlin Carver). She felt like she had lost her identity at some point and became as “paper” as Orlando and everything in it, so she came up to this town to do some serious thinking and find her identity. He asks her where he fits in to all of this, and she says that she wanted him to be her first and last partner-in-crime with the pranks she pulled before she left, and she commends him for being better at the role than she expected. She then apologizes for the clues, for not being a better friend, and for ruining his last few weeks of high school, but he tells her that they wound up being the best few weeks of his life, for he went to his first party, cut class for the first time, and went on his first road trip, and none of that would’ve happened without her. Margo sees him off at the bus station (and she tells Quentin that she has kept in daily contact with her little sister Ruthie [Meg Crosbie] since she left), and they kiss each other goodbye before he goes. Quentin immediately heads to the prom once he gets back and finds and joins his friends in the celebration.
In the scenes that follow, Quentin and company continued to hang out together after graduation and through the summer before they all parted ways for their respective colleges in the fall. While all of this goes on, Quentin narrates that he was wrong about many things, especially with how he labeled Margo as anything other than a girl. He still believes that everyone gets a miracle, though, and he understood now that his miracle was having fun with his pals at the prom. He adds that, while we might not all get to experience a miracle, we can still have amazing adventures, meet exceptional people, and make indelible memories; the trick is to notice them before it’s too late. He says he has heard different rumors about what Margo has been doing since he last saw her, but he doesn’t listen to them, for he knows that, wherever she is or whatever she is doing, it must be something cool but that’s her story to tell.