DISCLAIMERS: I don't own anthing other than the plot. J.K. owns the characters and I just borrowed them to play with.

A/n: This story is being revised and re-posted, I'm hoping to fix all mistakes, but it's possible that I missed a few mistakes...

THIS STORY WILL BE SLASH, if you don't like it, please just leave it.

re-posted 08/17/2013

italic = memory

Chapter 1 – The Dragon Pox.

Severus Snape didn't know exactly how it had all started. The truth is that he was still irritated by the fact that Slytherin had lost not only the game, but the quidditch cup as well, and that was when they had a hundred and fifty points of advantage! Two weeks had passed, and he still couldn't shake the knowledge that all of his problems were caused by one person. A griffindor that seemed to exist just to make his life a living hell.

With the ultimate care, Severus went back to the potion he was making. One of the worst stages of it was the addition of the Mimbulus mimbletonia root, and he added it with his gloved hand. HOW Harry Potter had managed to get Dragon Pox was a mystery not only to him, but to the school nurse, as well. Anyway, it was all Potter's fault, the fact that he was there, making the anti-pox potion instead of grading, or starting to make the wolfsbane potion for that damned werewolf.

It was a satisfied Severus who bottled the potion and took it to the hospital wing. At least while the boy was there, Severus didn't need to worry about another spoiled potion in his classroom. After delivering the potion, Snape went back to his dungeons, where he sat, ready to make spiteful notes on the badly done essays.

Unfortunately, his quiet moment was broken not ten minutes later by a frantic nurse, who showed up without announcement in his fireplace.

"What is it this time, Poppy?" he asked annoyed "What did Potter managed to do now? Did he managed to escape his bed even as weak as he is?"

"No, Severus, but... he had a major reaction to the potion! He can barely breathe! I had to do a tracheotomy on him!"

"Potter had an allergic reaction?" asked Snape doubtful, and without losing another second he used the floo to go into the hospital wing and see for himself what Potter had gotten himself into this time.

The scene wasn't pretty. Potter lied on one of the beds, all swollen, the skin green, like was expected in someone who had the dragon pox, and eruptions covered his skin, and, obviously, his throat had a hole, so he could breath. He definitely had had an allergic reaction to the potion.

The professor's mind went to all possible reasons that could have got Potter in that state, and in the end, there was only one ingredient that could ha have done that. Going back to his lab, Severus started to make a new potion, this time, to counteract the allergy.

It was a good thing that this potion needed only half an hour to be done, so the professor was able to concentrate on an alternative medication to the actual Pox.

This time Severus stayed in the wing to see Pomfrey administer the potion, another bad reaction and Potter probably wouldn't survive. For their relief, the potion worked as expected and Potter went back to be perturbed only by the maladies caused by the Dragon Pox.

When Severus was back in his lab, doing another batch of anti-Pox potion – this time without the dangerous root – a strange thought crossed his mind.

This was a rare allergy. A really rare allergy. And it was also a hereditary allergy. One that simply didn't exist amongst the muggleborns. HOW exactly did Harry Potter got that allergy? Poppy would have known if the Potters had it, since she treated James Potter since before he was born.

And then another thought came to mind, while he was adding the white lily petals in the potion. A memory. One of his bests memories.

Lily, his lovely Lily was moaning beneath him. They're bodies united. Sweat covered their backs with every thrust he made. They lips joined in a heated kiss. Their hands caressing the others body, and she scratched his back, asking for more, more and more till they reached their high and they fell in the bed exhausted and satisfied. At least in that moment.

The end of the memory wasn't as good. Lily told him that she was in love with her husband. Told him that that moment, as intense as it was, was a mistake. That nothing could ever happen again between them. And then she left. Again. Knowing that he would keep that memory forever.

Severus almost dropped the spider's legs he had. That memory made him think of another fact. The fact that his family, the Prince family was one of the only ones who had that allergy. But no. Lily didn't got pregnant till a month later. And Harry was absolutely certainly a Potter. The hair! The attitude! He was the heir to the family name! There was no way in hell that Harry Potter could be Severus Snape's son. No way! And he wound prove it. All he needed was to convince Poppy to get him a bit of the boy's blood and all could go back to normal. Harry would still be a Potter e he would still be a single man, in love with a dead woman and childless. Absolutely. Right?

A/n: Reviews?