On a rainy day, the elite salaryman Amakusa Ryo almost falls down some stairs when he is saved by an ordinary high school girl named Arima Ichika. Ryo was dizzy from not eating breakfast, which worries Ichika and she offers him her lunch then runs off. Later when Ryo gets home, Ichika is in his living room and he finds out that she is actually his sister Rio's classmate. Ryo wants to thank Ichika for saving his life and offers to kiss her...
Also, I'm just friends 
with his little sister.
.كما أنّي صديقة شقيقته الصّغيرة لا أكثر
Außerdem bin ich nur mit
seiner Schwester befreundet.
Y soy amiga de su hermana menor.
Y soy amiga de su hermana pequeña.
Et puis,
je suis juste l’amie de sa petite sœur.
Inoltre, sono solo un'amica di sua sorella.
E sou apenas amiga da irmã dele.
И вообще, я просто подруга
его младшей сестры.