Severus has been spending his time in the muggle world, he didn't enjoy staying in a world where he couldn't make potions, use magic, or talk about his talents. He was staying in the muggle world because it was winter break and they had extended it for a few weeks because of something that came up. He's already been dreading living with his parents, his father yelled and his mother neglected him like a penny on the ground.
He was sick and tired of how he was living, ever since he was little he has suffered through the constant abuse, which was physical and verbal. He couldn't call anyone because he didn't know anyone, and his father didn't let him touch the house phone. That's all his father cared about.
Rule Number 1. Don't touch the house phone.
Yeah, he had rules in this already broken down house. He wasn't sure why they even existed but he followed them nonetheless, he wouldn't want to get an earful from his father with his mom watching and doing nothing. Typical.
He was walking by a spot and that's when he spotted something–or rather someone. He wasn't sure who, but he didn't know them. That's when he realized, they too were from the magical world because he's heard of these type of people. Only few existed but he couldn't believe it, he's seeing one right now.
A person who's half Selma..he could tell because of what he wrote down on one of his journals– "Descriptions of Half Human and Half Beasts."