Your little sister, Natsuki, suddenly shows up in the middle of your busy days. Apparently she came to take care of you while she was on her summer vacation. This is the story about you and Natsuki one summer
I thought you were living a bit more 
carefree since you were living on your own.
ظننتك تعيش بتراخٍ أكثر
بما أنّك تعيش وحيداً
Ich dachte eigentlich,
du lässt dich etwas mehr hängen.
Creí que te sentías libre
viviendo solo.
Pensaba que te sentías libre
viviendo solo.
Je pensais que t’avais une vie
plus tranquille que ça…
Credevo che vivessi un po' più spensierato
 ora che abiti qui solo.
Achei que você estaria mais animado, 
já que está morando sozinho.