Sometimes red is the color of blood, the color of hurt. The color of the sky, as you realize whether or not you die is completely in the hands of someone else. Red, the color of anguish, pain, and regret.
But, there is a reason that red is the color for Christmas.
Red can represent worry and death, but red can also represent good cheer. Paired with the green of pine trees, the sight of the two colors can gift a pleasant feeling to anyone looking at it. Red is the color of action and energy. Red is for roses, red is for passion.
Red is the motive, the goal. Red can remind you of what you're fighting for.
And in this case, you're fighting for all of Western civilization. But sometimes when one has that much of a burden on her shoulders, she can't help but cry. She doesn't know if one day she'll wake up in a pool of her own red, and fade away from existence. She's scared.
Sometimes when her feelings become too much to bear, Annabeth will simply curl up on Percy's bed and cry. She doesn't need to say anything, he understands.
He doesn't like to see her cry. One night, he especially doesn't want to. Percy feels like she needs some red. (No, not that kind of red, you pervert.)
So when he appears by her side again with a bouquet of fresh roses, she stops crying. She sniffs it, the scent of flowers enter her system. Not just flowers, she smells red. And it comforts her.
She is reminded of her usual energy and adrenaline. She is reminded of the passion her friends and family have for her. She knows again that this is the motive. Annabeth will be stressed, she will be tired. But after everything is done and gone, it will be worth it. She's certain.
Percy smiles at her. She takes the roses, she takes in the feeling of red. It's a surprise what the color can do to help her emotional state. Red is the savior.
And for the first time in months, as she looks at the roses, she smiles.