This little sister Riko can't show her true feelings to oniichan and
even though she deeply loves him at heart, she shows a curt attitude instead.

But one day oniichan broke both of his arms when protecting Riko from a traffic accident.
While onii-chan has trouble with his everyday tasks, Riko helps him out.

"I-It's not that I like you or anything, I was just asked by mom to do it!"

Her caring covers not only your meals and bath taking, but also...

"I... I love you onii-chan."

[Edited from DLsite]