The baby wouldn't stop crying, and Lily was beyond frazzled. She was a new mother who didn't understand what her son wanted. She had tried everything, and still her tiny son was shrieking into her ear.
"Love, can't you get the baby to stop crying?" James asked wincing at the volume of noise one tiny child could make.
"I've tried everything, James. I've fed him. I've changed him. I've walked around with him. I've even tried singing to him. Nothing has worked! He just keeps crying!" She shouted over her son's screams.
"Here," James held out his arms for the baby, "let me have him."
Lily gratefully handed over the fussing child. Harry's crying over paused briefly before he continued crying as loudly as his tiny lungs would permit him.
"Harry, listen to your father. Stop crying! Go to sleep! Stop crying!" James shouted at the tiny baby as though Harry could understand.
It didn't help, and Harry's crying only seemed to get louder rather than quieter. The new parents looked at one another helplessly at Harry cried as his father held him.
"What's wrong with him?" James demanded of Lily. "Why won't he stop crying?"
"Don't look at me! I don't know!"
"You're his mother!"
"And you're his father! Despite what you men think women don't have some magical ability to know what their children want!"
James opened his mouth to respond, but a loud pop interrupted their argument. Only he and Lily ever apparated directly into the house. Not even Sirius directly apparated into their home. James felt adrenaline coursing through his body as he mentally began calculating how he could protect Lily and Harry from the intruder.
"I can tell you what it is your son wants," a smooth female voice declared from behind him.
Lily's face was surprised, but she didn't show fear as she would if it had been Voldemort or one of his Death Eaters. James turned around slowly and covered his son as best as he could with his arms.
The woman before him was only a little older than him and his wife. She had long blonde hair that was pulled back from her face in an elaborate but tasteful style. She wore lavender robes, and held a pink bundle in her arms in a similar posture as James.
"You son is old enough to realize his loss. He wants his Amoverus," The woman explained stepping forward into the room further.
Lily gasped as James asked, "His Amoverus? What's that?" The stranger ignored him, so James turned to his wife who seemed to have an idea. "What is it?"
"Amoverus. True love. Soul mate. It's a myth, though. It can't be true," Lily said the last to the woman who now laid down the bundle in her arms gently in Harry's crib.
She pulled away the pink blanket to reveal a tiny baby girl about the same age as Harry as she replied, "It is not a myth. This one belongs to your son."
She stepped back reverently and held out her arms for Harry. James hesitated to hand over his son so blithely. "I don't understand. What is Amoverus?"
"I can't very well explain it over your son's screaming, now can I? Give him to me, and you will see for yourself."
James looked at Lily who nodded for him to hand over her son before capitulating. He handed over his son awkwardly still unsure and new to holding and handling the breakable form of a baby. The stranger took the still crying boy and carefully laid him beside the peaceful girl in the crib.
James and Lily watched amazed as Harry stopped crying almost at once. The little boy turned his big head and looked with his big green eyes at the girl lying complacently beside him. James felt himself grin foolishly as Harry began giggling and laughing. The girl beside him also laughed. Lily joined her husband at his side as though pulled by an unseen force. James placed an arm around his wife's shoulders as the two infants clasped two tiny, pudgy little hands and fell asleep.
"How—What just happened?" James asked looking at his wife and then to the stranger.
Both women had a similar love-struck expression. They glowed from the touching exchange between the babies. James found himself smiling uncontrollably as he looked at the two children. The girl sucked the thumb of her free hand, and his son slept peacefully with his head still turned towards the girl.
"Your son was born incomplete, processing only half of himself. He realized this today, and needed his other half, his Amoverus."
"This girl is the Amoverus?"
"I don't understand," James said shaking his head and looking at his wife.
"There is a myth that great wizards are too powerful to exist in one body, so they are born literally in two, male and female. They are meant to find one another and live as one or live incompletely," Lily began explaining stepping up to the side of the crib to gaze at her son and the tiny girl.
"Are you saying half of Harry lives in this girl?" James asked trying to wrap his mind around this.
"It's only a myth, a legend. It's not supposed to be real."
"It's not a myth or a legend," the stranger said stepping to the crib as well. "It is very rare. There are almost none to keep a watch for it anymore, but there are a few of us who still watch the stars and read the signs.
"She was born three days after your son. I am her guardian. She has no family beyond your son and you."
"Are we supposed to take care of her?" James asked fearfully. He has only begun to absorb the fact that he was father to one. Father of two would be too great a hurdle to overcome just then.
"No," the stranger said shaking her head gently. "I will care for her. The children should be raised in close contact but not as siblings."
"What is her name?" Lily asked accepting this all much better than her husband.
"You have not given her one yet."
"We have to name her, too!" James said feeling manically frantic.
"Olivia Rose," Lily said quietly looking at the girl with a soft motherly expression. She looked up to find her husband's head nearly bursting with overload and explained, "It's what we would have named Harry if he'd been a girl."
"I still don't understand what's going on," James said confused and ignorant.
"You will, Mr. Potter. You will," the stranger replied as the three watched the peaceful scene in the crib with adoring gazes.
None of them could have guessed how this couple would affect history.