You can read the whole manga in an hour. This is basically an evolving love story between non-blood-related siblings. The male MC discovers they are not genetically related in the first chapter, and everything continues after that. To my surprise, this is a simple, well-built story. Their family time and love are evolving into true love for each other. There may be some tropes, but the side characters are a great addition. It's also very interesting to see the parents actively help them get together. This manga is the correct way to express natural and possibly healthy love between step siblings.