A class observation day was scheduled to be held in Gaku's class. However, Gaku was worried that if Hayato took a day off to attend, it would cause inconvenience at his workplace and increase his workload.
To keeping this secret until the end of visitation day!
Bis der Elternbesuchstag vorbei ist,
¡Mantendremos el secreto…
On doit tous garder le secret
jusqu’au jour des portes ouvertes !
Manterremo il segreto 
fino al giorno della visita!
É o nosso segredo até o fim da visitação!
Пока не закончится назначенный день,