Futaro is hospitalized for a while after falling sick at camp school. He returns to work tutoring the quintuplets, only to realize someone has fallen way behind.
Why are you so serious today?
Wieso bist du denn heute so verbissen?
Pourquoi ça t’inquiète tant,
tout à coup ?
Perché oggi sei così serio?
Por que ele está tão sério hoje?
Ты сегодня на удивление серьёзный...