Syunso has been seeming off lately and while the cause is unclear, it's likely because he has been unable to make any progress on his art since they haven't found the black cat. When Syunso forgets his pencil case one day, Mei heads to his school to bring it to him and is mistaken for his girlfriend by his classmates and a huge uproar ensues. The pair escape the chaos by ducking into an empty classroom where they are found by Syunso's best friend, Yokoyama Taikan. Taiken notices something strange in Syunso's eyes and urges him to go to the doctor immediately.
so he must have grabbed that 
one on his way out by mistake.
así que debió tomarla
por error al salir.
así que debió cogerla
por error al salir.
deve averle confuse per sbaglio mentre usciva.
então ele deve ter pego 
por engano quando saia.
должно быть, он перепутал
и забрал его с собой.