Katara doesn't say anything the first time it happens.
The hurt is still too fresh, too raw and she knows Sokka just needs time.
Even so, the urge to take her bring brother into her arms, to hold him tight and stroke his hair, to tell him that she's sorry and that she loves him and that she's here for him is nearly overwhelming.
But Katara doesn't, because she isn't sure if it would help, or just make it worse. She isn't sure of anything right now, and that simple fact throws her world off balance. Her stomach lurches, her throat is heavy as she watches Sokka sit in utter silence beside Aang, pretending to listen to the Avatar, but not catching a word.
Sokka looks different now, and at first she can't place it. She watches him quietly, her knees drawn to her chest and when the clouds roll by overhead, bathing Sokka in the light of the full moon, Katara sees the difference, glaringly obvious. Her brother looks older now, older and yet somehow smaller, illuminated and yet hidden in the white light. She realizes, in that moment, for all of her strength, for all her determination, for all her love, she can't help him.
The second time is even harder than the first.
There are no clouds in the sky tonight. The full moon shines across the northern water tribe and Katara feels strong, she feels the push and pull of the waves around her, feels the ice and snow in every structure, every pillar, even the moisture in the air, all of it drums through her veins and she knows that with just a gentle shifting of her fingertips she could bring it all down, or she could build it higher.
She isn't sure that Aang understands. Maybe it's because she's surpassed him in their training, but it's far more likely that it's because he's the avatar, and he's in constant connection with the Earth and the spirits. Maybe he feels like this all the time, and she's curious to know, but she doesn't ask. Instead she giggles as he beams at her, delighted to see how enthusiastic she is tonight, how the water around her shifts with each step she takes. Aang rides on and air scooter beside her, around her, moving in circles and she teases the ice of the bridge they walk on, sloping it, making a ramp for him to rush off of, laughing as he soars high into the air, and she laughs too, running along the ice, head tilted up, watching and laughing, smiling as power thrums through her veins. She is alive, she is alive, and she is strong.
Katara bumps into her brother halfway across the bridge as she's in mid-run. She nearly falls over from the impact, but her reflexes are faster tonight and a steady stream from the river below catches her, steadies her, and she laughs, breathless and smiling. "Hey Sokka!" He smiles at her too, but it's heavy and though he tries his best to hide it from her, she can see the dullness reflected in his eyes. Still, he tries to keep his voice light.
"Hey Katara, having fun?"
Aang floats down gently behind him, grin ever present on his lips but Katara feels her high starting to come down. She wonders what was Sokka doing out here so late at night. Was he wandering alone in the moonlight? Was he stopping atop archways and bridges, atop the highest points in the city, trying to somehow be closer to the moon? To be closer to the princess he lost?
Frustration wells under Katara's skin, along with power. The moon is full tonight, it's energy and light are strong and it fills her with such strength, such overwhelming joy, but she cannot share this feeling with Sokka. Her joy is his sorrow, and for all strength she feels, for all the water around her, she is powerless.
The bridge of ice beneath them cracks under their feet, and the sound is so sharp and heavy that it fills the lengthening silence between the siblings. Sokka shifts, uncomfortable for a split second before he lets out an exaggerated yawn and stretches his arms over his head. "Whelp, I'm pooped! I'm gonna go to bed. Have fun out here you two!" He turns to leave but Katara twitches her fingers and water wraps around his wrist, pulling him back, almost making him trip. "Gah! What the hell Katara?"
She wants to confront him in that moment, wants him to stop pretending everything is okay and that he isn't hurting. Instead she fakes a smile and says, "We're gonna be off fighting the fire nation soon, right?"
"Uh yeah, duh."
"Well them, you should probably practice fighting against a bender."
He blinks at her, seeing past her smile and tugs at his wrist, trying to wretch it free, but the current is strong and keeps him in place. "I think I've had enough practice already, Katara. Could you let me go?"
Her fingers twitch again and the current stops, the water freezing over the second it touches the ground. "Come on Sokka, lets spar!" She forces some enthusiasm into her voice, but Sokka's face twitches and she knows he can see right through her.
Thankfully, Aang was standing behind her, so he couldn't see her face, and he didn't realize what was wrong. "Hey! Thanks a great idea Katara!" But Sokka doesn't agree and takes a step back, "Uh,"
Katara tries to smile at him again, "Come on! We can go to the training arena, it's not that far." She reaches for her brother's wrist, but he pulls back before they touch and shakes his head, finally managing to look into her eyes. "Katara," he begins, his voice quiet, "I appreciate what you're trying to do but…I really just wanna go to bed, okay?"
He doesn't wait for her to reply before he wishes them a halfhearted 'goodnight' and turns away, walking off the bridge. Pain and frustration fill her all at once and the water moves on its own, rising from beneath the bridge, reaching out for her brother, about to envelope him before Katara realizes what she's doing and calls it back, quietly returning it to the stream, and watching her brother's back until he turns a corner and leaves her line of sight.
"Um," Aang begins, and Katara doesn't look at him as she turns and walks past him, off the opposite side of the bridge, feeling further away from her brother than she ever has. "It's okay Aang." She smiles at him when he catches up to her, riding another air scooter. "Sokka's just tired is all," she says, talking for the sake of talking, trying to bury her emotions. "He was up all morning going over battle plans and stuff." Aang smiles at her, accepting what she says, but there's something in his eyes that tells her he suspects different. His silence reminds her so much of her brother that she clenches her fists and behind them the ice bridge that they had been standing on crumbles apart. If either of them noticed, or even heard the crash of ice slamming into water, they say nothing.
By the time the third full moon comes around, Katara's frustration has all but boiled over, and she has to leave the camp, unable to watch her brother sitting in the moonlight with his knees pulled up against his chest, and his eyes staring blank, listless, unfocused into their campfire.
She walks as far away as she can, until the light from their fire is nothing but a glimmer in the distance, until she stands at the very edge of a high cliff, overlooking the sea. The moon is large and strong in the sky, reflects brightly off the waves and she stares with her fists clenched at her sides and her jaw set tight until she feels a familiar hand on her shoulder, turning her around and suddenly she's being pulled into Sokka's arms.
She doesn't resist the embrace and he holds her tightly as she fists his shirt. He smells like home. He is her biggest comfort, her island in the sea, he keeps her steady and grounded and he's fought all of his life to protect her but now, when he needs her, she can't help him. She feels his hand in her hair, stroking absently and he's whispering to her, "Shh" and "It's okay" and, "I'm sorry".
It's only then that she realizes she's been sobbing heavily against his chest, her tears soaking through his shirt and she hates herself for it. Sokka is the one who should be crying, Katara is the one who should be holding him, she is the one who should be whispering over and over that she's sorry, that it'll be okay.
She shoves him back, angry and hurting and wanting, more than anything, to be able to do something. Tears flow endlessly down her cheeks and try as she might, she can't make them stop. "No, Sokka. No." She sniffles and chokes, "It's not fair."
He's looking in her eyes now, more honest then he's been in a long time. "I know, Katara." She clenches her fists so hard that her fingernails bite into her skin, drawing blood. Below them the sea roars and crashes against the rocks and when Sokka steps closer, Katara steps back, furiously wiping her tears away, but they don't stop.
"I…I just…I wish I could help you!" Her stomach lurches and churns and she feels sick with guilt. Was she really so selfish that she couldn't push aside her own feelings? He moves closer again, she moves back until she's at the very edge of the cliff. Sokka shakes his head at her, smiling softly and it's a genuine smile, so different than the ones he's been forcing recently. The sight makes her hiccup and focus on him through the film of tears.
"But you do help, Katara."
She scoffs at that, wiping her eyes.
"No, really, you do. You're my sister and you're my best friend and," he steps closer, "Having you around, being strong and watching my back…It helps a lot."
Her voice catches when she speaks, hiccups with her sobs. "I don't feel strong, Sokka. I'm weak and useless. How can I help you when I'm the one crying like a baby?"
Sokka's eyes are heavy with affection and compassion and when he reaches out to embrace her again she meets him halfway, nearly making him stumble as she wraps her arms around him, buries her face in his neck. She can feel the pulse under his skin and it's so calm and so steady that she can't help but feel steadier for it. He strokes her hair again and she remembers the last time he held her while she cried like this, after their mother died. Even back then when Sokka was hurting just as much as she was, he held her in his arms. He comforted her. "I'm so selfish." She whispers brokenly.
She can feel him shake his head and he squeezes her tight in his arms. "Katara, you're the most selfless person ever. You're not weak okay? You're not useless and you're not selfish. You're crying for me right now, you're sad because you know I'm sad and…you know that I can't cry and the fact that you're doing it for me…it…it helps, okay? I don't know how or why but," He buries his face in her hair and she holds him tighter, her tears hot on his neck. "I'm just really glad you're with me, and I'm glad you're not just pretending nothing is wrong and I love you a lot and…just…thank you."
Katara doesn't feel much better, she doesn't feel less selfish, and she certainly doesn't understand how crying in her big brother's arms can help but she also knows that Sokka would never lie to her. So she says the only think she can think of between choked sobs, "I love you too."
They stay like that, in each other's arms until the sun breaks over the horizon and warms their faces, drying the tears on their cheeks.