Snowy99

I have read that yaoi once but I forget the title. Uke travel abroad and there met seme. Seme made a bet with his frient that is to make uke fall in love with him. Uke fall in love with him and seme give uke a key. And uke come to know about the bet, heart broken and return to his country. Seme win the bet but he can't forget uke and follow him.

I want to ask you guys about the title of the yaoi manga ( I've already read that manga a long time ago and now I want to read it again but I can't remember the title), please help me!
The story is that uke was traveled abroad (I don't remember why) and there he met seme(rich guy). Seme invite uke to his house(big like a castle). Seme made a bet with his friend to made uke fall in love with him. And uke really fall in love,too. And seme gave uke a key (a key of his heart, he say). Uke come to know about that bet and he leave back to his country. Although seme won the bet but he can't forget about uke. And later he go find uke. That is, I don't remember the details. Please link me if you know about this .