Optimus sat with his digits laced together. He watched his medic argue with the human children as he had since they arrived. He knew they were just getting used to each other and they would soon understand that they were more than a team. They were a family.

He looked his medic up and down, not understanding the sudden attraction he had for his old friend. Sure, he loved the snot out of the medic, but it had been an I-got-your-back kind of love, not the love where he would have drug the medic to his berth.

Ratchet caught him looking at him. "What? Do I have mud on me?" He tried to peek at his aft and back, but he didn't see anything that warranted the Prime's attention.

Optimus saw his moment. "Come. I will wash you off." He led the medic to the wash racks and he turned the water on to a good temperature. Due to always running after the Decepticons and having the constant need for fuel, the Autobots rarely showered, and when they did, it felt wonderful. He knew Ratchet hadn't bathed since they arrived to Earth, but he had been with his friend in the showers back on Cybertron. They were not strangers to each other.

"I don't understand it. I haven't been out of the base often enough for me to get dirty, not as often as you have. How could I possibly have dirt on me?"

"Dirt has a way of collecting where you least expect it." The Prime guided the medic into the shower and under the water. They watched each other for a moment before Optimus lifted a bottle of soap off the rack. He worked the soap into a lather onto Ratchet's body and he massaged the bubbles into the creases of his armor. The mech made a soft rumble of gratitude and the water turned dark as it spiraled down the drain.

"I guess I am a little dirty," the medic confessed. He looked up at Optimus, not understanding the emotions in his friend's optics. He had not seen these emotions in him before...but there was an old one he recognized immediately. Affection.

He leaned against his friend as the Prime continued to work soap all over him working now at his hips and lower back. The medic gave a soft gasp and shuddered against the Prime.

"I am glad you are enjoying your bath," Optimus murmured. Laughter was bright in his optics and Ratchet couldn't help the smile as it grew. He splashed water at the Prime's chest.

"Quiet," he growled playfully. He felt like they were back on Cybertron. They were carefree now. He almost forgot about the war. Almost. "We have to finish up soon. Bumblebee should be returning from base. We should be there, you know."

"Let them wait for us," the Prime rumbled. He backed the medic into a corner, his mouth finding the sensitive cables in Ratchet's neck. His digits worked their way into the creases of his armor and he earned a surprised shiver and a quiet moan. He felt encouraged by these signs and he continued to please his friend.

Ratchet was surprised with Optimus' sudden change. He watched the Prime find all of his sensitive areas and his optics dimmed and threatened to roll back into his helm as he moaned. He held onto the larger mech's shoulders, feeling heat radiate off him. Then he understood, his optics widening in surprise.

"You're in heat, aren't you?"

He knew that mechs and femmes had heat cycles and they would often go after their closest friends for relief. But none of the Autobots, and as far as he knew, and none of the Decepticons had gone through their heat cycles in eons since they left Cybertron. Why now? He hoped that it meant the war was coming to an end, but a part of him didn't believe it completely.

"It would seem that I am. Perhaps you can assist?" The Prime murmured into his neck as he turne the medic around and he crushed the smaller mech into the wall.

"I seem to have no choice in the matter," the medic said softly as he submitted to the mech. He pushed his aft back against the Prime.

"No, it appears you don't."

Arcee walked into the base, looking around. "Where are Optimus and Ratchet?"

The children looked up from their game. Bumblebee's doorwings lifted and fell as he chirped and whistled.

"In the wash racks?" Arcee frowned and looked back at Bulkhead. "Together?"

"They were best friends on Cybertron, Arcee. Practically brothers."

"Yes, I know, but it's been a while since any of us has stepped pede in the wash racks. Do you think Optimus is hurt?"

Jack piped up. "He did look a little weird when he left with Ratchet. He had convinced Ratchet that he was dirty, but we didn't see anything."

"Optimus may have been wounded and he didn't want to worry anyone. Typical Optimus," Bulkhead said.

"We'd better check on them," Arcee said. She started walking to the wash racks with Bulkhead and Bumblebee at her heels. She heard purring and soft murmurs coming from one of the stalls. She frowned. It didn't sound like a Prime in pain or a medic treating a patient.

She peeked into the stall and her optics widened.

Optimus was sitting with Ratchet in his lap, water rinsing away the evidence of fluid. The Prime was still buried in the medic's valve as he kissed Ratchet's face and neck. He looked up when he heard Bumblebee's doorwings rattle against each other and he gave a small smile to them, startling his team. "Would you get a towel for us? Ratchet has gotten a little...messy."

The scout's optics dimmed and rolled back into his helm as he fell backwards into Bulkhead.

"I hope he recovers soon," Optimus murmured, taking the towel Arcee offered. He wrapped it around Ratchet's hips, then he pulled away with a pop. He knelt over the scout and he watched the little yellow and black mech come around. "Ratchet is in no position to treat you if you are wounded. I suggest you take it easy and go back to your quarters to rest. I will send Ratchet when he is done servicing me."

The scout's optics widened and he laid his helm back down while his leader and his medic walked out.

Bulkhead blinked repeatedly. "Any chance we can un-see that?"

Arcee shook her helm as she crossed her arms, a smile growing. "Nope. You know what this means."

Bumblebee whistled lowly, his frame shaking against the floor.

"That's right, Bee. Heat cycles."

Ratchet laid in Optimus' berth, watching the Prime's face as he hugged his neck. He knew this was just a heat cycle and no love was involved, which he regretted. He kissed the Prime's neck and audio, helping the mech inside.

The Prime pinned the medic down as he gave soft thrusts, which was unusual in heated mechs. He was surprisingly gentle and giving, not rough and demanding as Ratchet had expected, especially from a massive mech like Optimus.

When the Prime finished, he laid beside the medic and he kissed his neck and face. He pulled the medic onto his chest and he gave a small smile up at him. "I love you."

It's just the heat cycle talking, Ratchet reminded himself as his spark started hamering in its chamber. He pressed his face into the mech's chest.

"Do you not love me back?" Optimus lifted his face to his.

"It's just the heat cycle talking," Ratchet said finally. "You're not yourself."

The Prime's optics narrowed momentarily as he thought, then he kissed the mech gently, holding his face. "I am myself. I am Optimus Prime, leader of the Autobots. I was formerly Orion Pax, data clerk in the Iacon Hall of Records. I dated you briefly, very briefly, but you went to one base and I had to go to another as I was a Prime then. I-"

Ratchet scoffed, disrupting him, but he couldn't help himself. He blushed pink. "But you're in heat. You shouldn't be thinking this clearly..."

"I may be in heat," the Prime murmured. "But I am in love with you."

The medic opened his mouth to protest, but the Prime effectively silenced him with another kiss.

"Let me speak. I desire you as my mate."

"Optimus..."

He kissed his face. "We can do it. We can last. I know we can. If we bond..."

"What if you die?" The medic pushed at his chest and he sat up. "What if you die? Then what?"

"I will not die," the Prime whispered. He rubbed the medic's sides. "I promise."

"You can't promise not to die. Anything can happen."

"What is life without a little risk?" He kissed the medic's digits. "I am putting my spark on the line for you."

"You are a fool," Ratchet protested weakly. He was losing his reluctance.

"I am not convinced you do not want this," he scoffed. "You must try harder in order to convince me."

The medic tried to actually glare down at him as he lifted off the Prime. "Why do you have to be so persuasive?"

"I have to be in order to maintain peace."

"How's that working out for you, O Powerful Prime?"

"It is going according to its own plan and has not invited me to any of its meetings, unfortunately."

"Shame."

The Prime chuckled softly as he rubbed the medic's hips. "Am I to assume that this means you want to be my mate?"

When the silence grew between them, the Prime opened his mouth to say something, but Ratchet pressed a kiss to his lips, surprising him.

"What do you think, Prime?"

Optimus rumbled affectionately and he rolled over onto the medic. "I knew you would come around eventually."