Tsukasa and Nasa are closer than ever to unlocking the mystery of her eternal curse, but Tsukasa finds herself haunted by memories of the past. Things only get more emo when the newlyweds are called upon to tend the Yuzaki family grave, which reminds Nasa of his eccentric grandfather, a WWII vet who claimed to have met a demon. On the bright side, Nasa finally gets the technological inspiration he needs—by obsessing over swimsuits!