Amai Akuma ga Warau (Love is the Devil)

Synopsis

Haruru Shirosaki, a girl whose father is a director, is always busy. Her best friend is Mami. She visits a girl's school across the road from a boy's school. One day she sees a boy in the window of the boy's school. When she comes home from school the boy she had seen earlier is there saying he will become her butler? Is this just a dream?