Koneko Hiroimashita

Koneko Hiroimashita (子猫拾いました) is a manga series by Yohachi. It had a sequel under the name Koneko Mata Hiroimashita (子猫また拾いました).

Plot
Atsuki Komiya is a college student that's living alone. Suddenly, his sister visits and asks for a favor, which is to take care of his niece, Kasane, for two weeks. A story about the awkward relationship of these two, the confused Atsuki and the sullen Kasane, living together. Which direction will this story go…?