It starts as a typical story, guy made childhood promise that he forgot and is forced to live with people who expected him to follow through. It also ends pretty predictable with parent consent and everyone accepting everything including side characters. At some point in the middle, though, it goes to crazy places of the yandere kind, also a trap.

In any case it's a variant of the typical imouto story. If you like the art go for it, it's short and it has a complete ending with epilogues and everything; but if it looks too much like a beginner trying to draw like anime then you're not missing anything if you step away.