Bougyaku no Kokekko

Yuu Enji, abandoned by his father, is the oldest child in a foster home and dreams of buying it so everyone there can live happily together. Fed up with adults such as the selfish principal of his orphanage, he decides to get a job and attends his high school graduation with that goal in mind. But on the day of his graduation, the world suddenly changes: adults begin transforming into giant chickens and attacking children. Yuu must protect the children in his care while trying to hold on to his dream.