Scapegoat Sister Vs Second Prince

The second prince has come of age. To celebrate the advent of such an occasion, the search for a suitable bride began. My younger sister was expected to go to the Royal Palace as a candidate. However, despite this, she eloped the day before her departure. I, the older sister she left behind, looked almost exactly like her – so much that we were often mistaken for twins… One month, right? For just one month, shall I substitute in for my sister? — Description from novelcodex.org