Working Musume.

Saki, an ordinary 14-year-old girl is very stingy and loves money. One day after her parents and little sister and brother mysteriously disappear, she finds 2 guys at her door. According to the handsome one, Takumi, her father lost his job a long time ago, and had incurred massive debts at Takumi's firm. In exchange for saving Saki from a loanshark, Takumi asks her to work for him, to pay of her father's debt. What's a desperate girl to do? go work of course!
from (Source: M-U)