Disclaimer: I don't own Avatar, Katara, or Aang :D
Aang can't help but watch every curve in Katara's body as she easily moves through the water. He studies the flow of her arms, the way her figure moves with the water; Aang knows he's never seen anyone move through the element in such a way.
He's thrown out of his introspection when he feels hands wrap around his ankle. He doesn't have time to react, and soon enough Aang is pulled under the water.
In a brief moment of panic, Aang gropes for the closest thing to him, for something to help him regain his balance, it doesn't take long for him to find Katara's hand and she pulls him to the surface.
Suddenly Aang is so close to Katara, his heart is pounding. She's laughing, eyes gleaming, her dark brown hair sticking to the sides of her face, and Aang thinks he's falling in love all over again.
"That was revenge for earlier." Katara says playfully, and leans in to brush her lips against his cheek. Aang knows he isn't breathing, that he should say something, anything. Aang opens his mouth to speak but there isn't a thought in his head except for the vague thought that maybe revenge was all Katara wanted when she asked him to swim with her.
Still, he thought, revenge was pretty sweet.