A/N: This is for my 30-Day AU Challenge, which won't be updated every day considering I'm too busy for that, but it will be uploaded whenever possible until completed. Anyway, enjoy! Day's one prompt is; You share your temperature with your soulmate; they get a fever, so do you, and vice versa. Let's begin ;)

Fever Of The Heart

"Mommy, my head hurts." A six-year-old Hinata Shōyō pulled himself onto his parent's bed in the middle of the night on a cool April morning, muttering the words under his breath with an exhausted yawn. His mother, who was still mostly asleep, mumbled something unintelligible in response and rolled over, squinting up at her small, curly-haired son with tired brown eyes. "Hmm? What did you say, baby?"

"My head hurts," he repeated, eyes beginning to water. "I'm really hot."

His mother pushed herself to a sitting position and pulled the boy into her lap, placing a cool hand against his forehead. "Oh, Shōyō, you're burning up!" She stood up, cradling him in her arms, and hurried into the kitchen. She set Hinata down on the counter as she started searching through the cabinets for some cold medicine. "Oh dear, oh dear, where is it?"

"Mommy," Hinata whined, tears shining in his brown eyes, "it hurts. It's too hot." He was shaking from chills, and his whole body was covered in sweat. His mother paused in her frantic searching, random pill bottle still in hand, and turned to look at him. "Shōyō, did you just suddenly start feeling like this?"

The ginger nodded after a moment of hesitation. His mother sighed and shook her head, placing the bottle back in its place. "Shōyō, darling, I have something to tell you."

"What is it?" The child sniffled as she moved to stand in front of him, resting her hands on his small forearms. She smiled at him and smoothed the sweaty ginger curls back from his forehead. "You know about soulmates, right, Shō?" When the boy nodded, she continued on. "Well, this is something that can sometimes happen. Your soulmate shares the same body temperature as you, so when they get a fever, so do you. So when fevers are suddenly brought on like this, it usually means that somewhere, your soulmate is sick."

"Oh no." There was strong concern shining in Hinata's eyes as he gripped his mother's sleeve tightly. "I don't want my soulmate to be sick, Mommy. Can I help?"

His mother smiled at his sweet, innocent nature and pulled him into a hug. "Sure, baby. If you take some medicine and get lots of rest, then I'm sure your soulmate will get to feeling better very soon, okay?"

Hinata nodded enthusiastically. "Okay!" He wiggled impatiently in his mother's arms. "Hurry, Mommy, I want them to feel better as soon as possible!" His mother laughed and set him down, obediently gathering the medicine and delivering it to the impatient boy. He downed it all in one gulp, making a face at the bad taste, but managing to keep it down nonetheless.

"Now, to bed with you," his mother ordered, gently leading him back to his room. When she had tucked him safely under the covers again, she sat on the edge of his bed and brushed the hair back from his forehead. "You know, Shō, they have another name for the fevers you share with your soulmate."

The ginger looked up at her curiously. "What is it, Mommy?"

She smiled gently. "They call it a fever of the heart."

"That's the stupidest thing I've ever heard," Kageyama scoffed, glaring down at his ginger-haired teammate in disbelief. "'Fever of the heart'? Who even came up with some sappy shit like that, anyway?"

"Shut up, Bakageyama." Hinata's shout was dulled slightly by the loud sneeze that followed it, causing his whole body to shake. Sniffling and wiping at his nose, he glowered right back at the tall setter. "My mom told me that, so that means it's true!"

"You're such a dumbass." Kageyama flicked him on the forehead and Hinata gave a cry of protest. "Now get in position so I can toss to you." The ginger did as instructed, grumbling under his breath and shooting irritable looks Kageyama's way. Suga and Daichi watched from the side of the gym, having overheard the entire conversation, and had taken to discussing it themselves.

"I've never heard it called that before," Suga said, frowning slightly as he pondered to himself. "'Fever of the heart'. I guess it does fit, though, in technical terms... What do you think, Daichi?"

The captain laughed nervously. "Um, well... I guess it sounds more poetic than 'soulmate fever', doesn't it?"

"Oi, dumbass, what the hell was that?!" The two were jerked out of their pleasant conversation by Kageyama;s harsh yell, and turned to find the setter glaring down intimidatingly at the small spiker, who was shifting from foot to foot nervously. "That jump was half of your normal height!"

"Sorry..." Hinata murmured, which made Suga, Daichi, and even Kageyama take pause, because they all knew Hinata was one to fight back, and being this submissive, especially around Kageyama, was definitely weird. And now that Suga was looking more closely at him, the ginger did seem to be different from his normal self. His brown eyes didn't hold their usual enthusiastic sheen, and his movements were slow and clumsy; nothing like his usual bursts of quick, sporadic energy.

Kageyama studied him suspiciously. "It's fine... Just don't do it again." Seeming hesitant, he lowered back into setting position, and Hinata stepped to the back of the court in preparation for his toss. It went perfectly well; Kageyama threw the ball, Hinata ran with his usual speed, his hand aimed for the ball.

But then it all went bad. Hinata's hand missed the ball as he seemed to slump in midair, falling straight to the ground like a sack of flower. Kageyama, in an act of quick reflexes, had made to lunge forward and catch him, but his eyes seemed to go blank and he collapsed right next to Hinata.

Suga and Daichi rushed forward, shooing back the rest of the team, and rolled the boys over onto their backs, calling out their names and asking if they were alright. However, when Suga caught sight of their flushed cheeks and shaking limbs, his eyes flashed with understanding. "Oh. Oh." He covered his mouth and turned wide eyes to Daichi. "Soulmates."

Behind them, there was a collective gasp from the gathered members, aside from the snickers that came from Tsukishima and—by association—Yamaguchi. Daichi ran a hand through his hair with a grimace. "Oh god... I have a feeling those two are not going to be very happy about this..."

A/N: Short and kind of all over but it was the first try. Anyway, feel free to let me known comments, corrections, and suggestions down in the review section, and please follow and favorite if you enjoyed the story and want more. Anyway, until next time ;) Ciao~