Disclaimer: I don't own either Percy Jackson and the Olympians, Harry Potter, or the characters within their stories. They belong to Rick Riordan and JK Rowling, respectively.
"They're horrible muggles, Albus, you cannot possibly think it will be good for young Harry to be raised here. He'll know nothing of us, nor anything of our world. And I have been watching them all day. That brat of theirs is horrible and looks like a seal without the cute eyes, if Harry turns out like him, Lily will come back from the grave and haunt me."
An old man in a horribly tacky set of robes looked at the speaker, an elderly woman of Scottish descent. His eyes sparkled in a slightly creepy fashion as he spoke, "It does not matter, Minerva, it is our only possibility. The boy needs to be raised here, away from all the fame that our world has placed upon him. We don't want to give him a swelled head, after all. It would a complete disaster. Besides, I have placed blood wards around the house. Being here, with relatives who will no doubt love their kin, will create the strongest wards imaginable."
The Scotts woman frowned, obviously not liking the idea, but it was Albus, after all. Her old friend always did the right thing, and she could imagine Little Harry with a ego the size of Greenland: his father had been bad enough. She did not think she could handle someone with the level of narcissism that would result. She nodded. "Fine, but I will hold you accountable if this backfires. How's Hagrid holding up?"
"He's taking it hard, especially after young Sirius' betrayal. Such a thing to happen."
Minerva's lips thinned in displeasure, paling around the edges as she did so. "Indeed, I don't think any of us expected that." The old man stroked his long white beard and nodded, eyes glimmering. He put the young boy in a basket he pulled from what seemed to be nowhere, and placed a note on top of the boy to catch the attention of the one who found him. He delicately placed the basket on the doorstep, as the child began to cry.
"Good bye, Harry Potter, Boy-Who –Lived. I'll see you in a decade or so. I look forward to our meeting," the old man whispered. "Minerva," he said in a louder tone of voice, "It is time for us to go." He then turned and began to walk, until with a sharp 'pop' sounded and he disappeared.
The woman nodded, glancing at the child one last time in doubt, turned as well and popped away. The child continued to cry on the doorstep of the perfectly ordinary house, in a perfectly ordinary neighborhood. Little did he know that all around the country of Great Britain, many witches and wizards dressed in odd outfits raised their glass, stating: "To Harry Potter, The Boy-Who-Lived." Quite a few, on the other hand, cursed his name and his role in the demise of their master.
Neither the old man nor the stately woman, nor any of the others around the country know of the strange pair of kaleidoscope eyes watching the whole exchange, narrowing as the old man talked. The owner of the eyes had seen in to the mind of the old man, and seen his plans for "The Greater Good." Nobody treated children like that where she could see. "No one," the owner of the eyes said aloud, "Has the right to treat anyone like that, old man. Most certainly not my son."