Los hijos de la familia Shiunji, 6

Now that they know they are not related by blood, the Shiunji brothers begin to see each other in a different light. While the eldest son, Arata, tries to resist his sisters' advances, his twin, Ôka, feels overwhelmed by her own feelings. He escapes for the weekend to rest—or so he says—but, days later, he still doesn't return! Will Arata find her before she disappears forever?