The Pines family are about to go on a trip around Oregon! Pacifica is eagerly planning to use this as an opportunity to break into a Northwest facility that she believes to be another location of Stanford's illegal activities. Candy and Grenda are invited, of course, and Mabel is also going, but Dipper assumes that he's not going until Pacifica officially invites him. He's shocked and pleased, so he thanks her. Pacifica just smiles at him before walking off and oh man, has her smile always been that nice??
(He spends that night freaking out over it to Mabel. Mabel knows what's going on. Mabel's been planning for this. Mabel is ready.)
During the course of the trip, Mabel tries to relearn how to socialize with people and becomes friends with Candy and Grenda while Dipper awkwardly deals with his new crush(?). The two of them nearly die at the Northwest facility, but Mabel, Candy, and Grenda save them. That night, Dipper confesses his feelings to Pacifica, telling her how even when he hated her, he respected her and that he adores her confidence and kindness and that he could never deserve her. (There's also a quick peck on the cheek at the end there.) Pacifica responses by saying, yeah, he's been an absolute jerk to her, but the person he's becoming has a much better chance than who he used to be. She doesn't say yes, but she does say that maybe one day in the future it'll happen. And then she returns his kiss with a kiss of her own on his cheek. Dipper swoons.