The Heiress Episode 19

Han Shi Yi takes soldiers into battle. The Fifth Prince promises to give Han Shi Yi back her female identity when they return victorious. The Second Prince wants to give up the fight for the throne but is convinced by his uncle to keep fighting. The Han soldiers are in danger because the soldier sent by the emperor takes some soldiers and attacks on his own, ending in defeat for his soldiers. They send Han Shi Yi to get more soldiers, but the soldiers from the nearby city won't open the city gates. Han Shi Yi's dad dies in battle. Han Shi Yi goes back to find her dad and is ambushed. Han Shi Yi learns that the war was just a plan to get rid of her dad and the Han soldiers. She jumps off the cliff. (Source: jindreame at MyDramaList)