Deep as the Wine-Dark Sea.
Her legs are starting to cramp. Himawari ignores them and she doesn't move from Yuuko's garden, where she has been sitting down for what seemed forever ago, but the sunset tells her it has been, at most, two hours.
It doesn't matter how long she has been there, after all. What matters is how long they have not been, and that's the reason why she stays, unmoving.
'You don't have to say a thing,' Yuuko-san had said, her voice soft and careful, like falling leaves during autumn. 'It's not your voice but your faith what will help them.'
So she stays at the place where she had said goodbye to them, Tampopo perched on her shoulder. Watanuki had promised to make them strawberry shortcake when he came back and Doumeki had nodded at her silent pledge to please take care of them both. She wasn't able to go because of her bad luck. They'd need all the good luck they could find, without hers to darken theirs.
She knows what will happen if she speaks, because her luck is like that. She knows better than to hope for a happy reunion out loud, because her words and the meaning of them will be lost and she won't bring them pain.
Himawari is sure that they will come back. She can feel them, deep within her heart, on the careful touch of Doumeki's hand over her back, gentle, as if the scars could still hurt her, on the sweet way Watanuki has of touching the back of her hand gently.
She won't speak, but she will be praying for them and for them to come back, and deep within her heart she will be praying that they will hear her voice, and that they will come back to her side.