Romance (CHB)

Throughout the series, Percy and Annabeth have shown many romantic feelings for each other; mainly in The Last Olympian.

The Sea of Monsters
In The Sea of Monsters, Annabeth begins to show slight feelings for Percy. At the end of the book, she kisses him on the cheek following their success at the chariot race.

The Titan's Curse
In the third book, Percy found out that Annabeth almost became a Hunter at one point, and that the option is still open. Percy is terrified that Annabeth would leave him. Annabeth wanted to go back to holding the sky so Artemis could fight, but Percy took the weight. Later, while she seemed grateful to all of the people who rescued her, she expressed her gratitude mostly to Percy.

The Battle of the Labyrinth
During breakfast one day, Annabeth broke the rules and sat at Percy's table just to talk about their upcoming quest, which Percy liked. Annabeth got extremely jealous and moody every time Percy mentioned Rachel. In Mt. St. Helens, when Percy risked his life so Annabeth could get to safety, she kissed him and ran off. She and the rest of camp presumed he was dead, as he was stuck on Ogycia for two weeks. When he returns, Annabeth hugs him fiercely until she realized she was making a scene. She was furious at Percy for being gone so long, and when she figures out where he ended up, she gets even madder with extreme jealousy. Whenever Rachel was present or bonding with Percy in the Labyrinth, Annabeth got mad at Percy or stormed out of the room.

The Last Olympian
At camp, Throughout the war, Percy and Annabeth show some definite feelings for each other. While Percy was bathing in the River Styx, he had to choose one thing to think of to keep him anchored to the mortal world. He saw Annabeth pulling him out of a Camp Half-Blood lake. When Percy was about to get stabbed at his one weak point during a battle (he would've died immediately), Annabeth intercepted the blow. Percy immediately became very defensive of her, making sure no one touched her. Kronos found this interesting. When Annabeth was healing, she and Percy were talking. It was becoming a romantic moment, until a camper entered and said Grover had arrived. Every time a difficult task was at hand, Percy would volunteer either to protect Annabeth, or to ask for her help. Near the end, when Percy was offered immortality and life in Olympus, Annabeth was horrified that Percy would leave her, similar to the way Percy felt when she almost became a Hunter. He turns down the offer, mostly because of Annabeth, and she cries in relief. Back at camp, Annabeth has a private birthday for Percy, with a homemade cupcake. Percy confesses his vision in the River Styx. He tried to tell her how he feels about her, but Annabeth was smiling at him. Percy complained she wasn't making things easy for him, which Annabeth replied to by putting her arms around his neck and saying that she would never make things easy for him. She kissed him then, and Percy felt like he was melting, and that he could stay like that forever. However, campers interrupted and picked them both up, allowing them to hold hands. They dumped Percy and Annabeth into the river, expecting them to resurface. But because Percy is the son of Poseidon, he created an air bubble around the two of them, and they shared what Percy described as "the best underwater kiss of all time". They become boyfriend and girlfriend, which can be presumed as Percy says that they were "off to a great start" and when Grover says that he was Percy's best friend - "except for Annabeth", Percy replies by saying that "that's different", to which Grover agrees. As they leave Camp Half-Blood for the year, they race down the hill, and for the first time, Percy "didn't look back".