[Machine Translation] ( Da Vinci Book of the Year 2017 Novel Category 1st Prize ) ( King's Brunch Book Award 2017 ) Winner! One day, a mirror suddenly began to shine in front of Kokoro, who had been shut up in her room, unable to go anywhere. Seven people in similar circumstances were gathered in the world beyond the shining mirror. In the castle, where the hours are strictly observed, seven people search for a hidden key to fulfill the wish they have in their hearts.