Onee-chan Tasukete! ~Shoujo ga Ochiru Made~

お姉ちゃん助けて！～少女が堕ちるまで～

2006 Main Game Released

Summary:

Europe, 5th century A.D. Melvin family invades Burgundia and captures Helena royal princesses. Her sister Theodora struggles as a military commander, but is defeated. Melvin commander Julian is fascinated by Theodora's nobility and courage. Eventually it transforms into desire to corrupt her.