Cuckoo no Iinazuke

Exchanged with another family's child when he was a baby, Nagi Umino finally meets his biological parents. That day, he also meets Erika Amano, the other baby he was exchanged with. Nagi learns above all that their two families have unilaterally decided to betroth the two children! Now they are forced to live together: Nagi the serious high school student and Erika with a fiery personality. What will become of this strange couple?