Hito Natsu Kagiri no Jouji

Grace works for a charity group that volunteers at an orphanage in Africa. While she's vacationing in the Algarve, she hears that Marco Aguilar, a famous billionaire who was apparently an orphan before becoming successful, is returning home to the Algarve for work. Grace expects Marco to show concern for the kids in Africa and agree to donate to the orphanage, but instead Marco accuses Grace of trying to expose his past. Eventually, he decides to offer her a large donation for the orphanage, but he wants her to spend the rest of her vacation with him in exchange... (Source: Renta!)