Nozomu has come to a foreign country named Alusamito in order to chaperone his younger sister. She is there to attend a marriage interview with a prince, due to Nozomu's family's financial situation. It turns out that the marriage partner is Nozomu's childhood friend, Laud, whom he used to play with long ago. But Laud has changed from the nice boy he used to know into an arrogant, unlovable man!

Laud suggests to Nozomu, who is already worried about his sister becoming only one of Laud's wives, that he should take his sister's place and marry him…!?