Tenka Touitsu Koi no Ran ~ Shutsujin! Saika 4-nin Shuu

During the 15th century in Japan, frequent conflicts among regional lords disrupt the land. After losing your father in combat, you help your mother run the family restaurant left behind. When a corrupt magistrate takes your younger brother and forces him into a role as a poison taster, you take action to protect him by disguising yourself as a boy and taking his place at the castle. What you encounter there extends beyond your expectations. Amid the Sengoku period, romantic entanglements emerge as a perilous struggle.