"Everyone looks pretty grown-up after summer break"
Shinpachi finds himself in stuck in a completely different world.  That is when the Shinsengumi sends a berserk Yamazaki to pick up the bewildered Shinpachi.
I was also left behind two years, just like you.
A mí también me dejaron atrás hace dos años, como a ti.
Também me deixaram para trás 
esses dois anos, como você.