Sugar, It's Cold Outside (слэш)

Riddle kept odd hours, coming and going at all times of the day and night. He was always dressed in sharp, expensive suits, and Harry often saw Riddle arguing in low, harsh whispers over the phone whenever they crossed paths in the corridor. It was hard to imagine what someone like that was doing living in a cheap flat like the ones in their building.
“He’s just like that,” Hermione had said, when Harry raised concerns over their often-absent neighbour. “We’ve tried reaching out to him before, but he just doesn’t care to socialize.”
Harry Potter only ever sees his elusive, handsome neighbour Tom Riddle when Riddle wants to borrow a bit of sugar. However, an embarrassing incident leads to Tom taking a sudden interest in Harry, which quickly gets out of hand. Never let it be said that Tom Riddle doesn't get what he wants.