The Lost Hero
Jason first meets Piper on the Wilderness School bus. They are holding hands as Piper believes that they are dating; but Jason, whose memories were wiped by Hera, does not remember. After she is thrown over the Grand Canyon while fighting a ventus, Jason jumps over the edge to save her. He grabs Piper mid-fall, and the air buoys them up due to his powers. In his mind, Jason feels a little tempted to kiss her when they hold each other like that. Jason mentions that he did not leave her when she was knocked out.
Piper believes she had developed feelings for Jason during the school year, but it was all a trick of the Mist. When Aphrodite claims Piper at camp, cladding her in a beautiful dress and perfecting her hair and makeup, Jason unconsciously calls her a "knockout." It is also revealed that Jason was very protective of her when she was knocked out due to the vision from Hera/Juno.
When they are going to see Boreas, the area is extremely cold, and Jason unthinkingly takes Piper's hand. However, their hands are frozen by Khione. As they continue on, Jason notices that Aphrodite's magic is wearing off, yet, in he prefers her normal appearance. With the blessing, she seemed almost out of his league, while her normal appearance is someone he could hang out with. At the same time, he realizes that Piper with the Aphrodite blessing is just another side of Piper, even though she tries to hide it.
After dealing with some cyclopes, Jason, Piper, and Leo reach Chicago, and they enter the sewers in search of the venti. While they eat, Jason can't help but think he wants to be alone with Piper; and soon, she curls up to sleep on him.
At Pikes Peak, Jason holds Piper in his arms so they can stay warm. Piper reminisces about her father and finally gathers the courage to tell her friends about how her father has been kidnapped by Enceladus.
After escaping Aeolus, Piper has a dream about her and Jason. She had asked him to the roof of the Wilderness School under pretense of watching a meteor shower. Jason wonders why Leo didn't come, but Piper tells him she didn't invite him. They slow dance and kiss, but then her dream dissolves.
When they return from their quest, Piper challenges Drew Tanaka for the role of Aphrodite cabin head counselor. She succeeds, and as a last comment, Piper tells Drew to stay away from Jason. At the end of the book, they meet in the common area. Over there, they don't kiss, much to the dismay of the Aphrodite campers who had been betting on that.
Leo Valdez And The Quest For Buford
Leo states that the two are now an official couple, and that Piper looks a lot happier. She also gives Jason a goodbye kiss in case she never sees him again.
The Mark Of Athena
Annabeth addresses Jason as Piper's boyfriend, which shows that the two have officially started a romantic relationship. Jason reveals to Piper that he prefers her over Reyna, someone he had worked closely beside in Camp Jupiter. Piper tells him that she loves him while they are drowning, even though they both survive.
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