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.
The one who does the worst is the culprit.
Diejenige, die die wenigsten
lösen kann, ist die Täterin.
A quien le vaya peor será la culpable.
A quien le salga peor será la culpable.
Celle qui obtiendra la pire note
est la coupable.
Chi andrà peggio è la colpevole.
A culpada vai ser a que se sair pior.
Кто справится хуже всех —
 и есть виновница.