Su Qingwan, the daughter of a drug dealer in Nancheng, had three hobbies in her life: identifying medicines, preparing poisons, and making abacus. In troubled times, the family business is in turmoil. The Su Family Medicine Store, which used to be a bustling business, now only has an empty shop and a lot of bad debts. In order to protect his ancestral property and leave a way for the people to survive in this age when human life is at stake, Su Qingwan returned to his old business. Only this time, her medicine is not only sold to ordinary people. The upstart from the east of the city, the legendary iron-fisted warlord Shen Du, became her biggest patron. He sees her as a cash cow, and she sees him as a talisman. In a contract, she provided golden sore medicine to his army on the condition that he protect her trade routes and turn a blind eye to her "loss-making business" of secretly relieving the refugees. The two have a tacit understanding, repeatedly jumping on the edge of calculation and cooperation. Shen Du thought that what he held in his hands was just a smart businesswoman, but little did he know that this girl's abacus beads were crackling. She not only clearly understood his military expenditure, but also quietly spread the seeds of humanitarianism all over the scorched earth. Su Qingwan thought she was embracing a cold-blooded and iron-blooded patron, but she never expected that the warlord leader would clumsily hand her a bowl of hot porridge when she was exhausted from taking medicine late at night; that he would use his body as a shield to protect her when the enemy was besieging the city. Later, the accounts were calculated, from the balance of money and goods to the debt of favor. Shen Du pushed her against the corner with deep eyes: "Boss Su, what medicine are you going to use in exchange for my life?" Su Qingwan smiled brightly and touched his Adam's apple with her fingertips: "Commander, my medicine... Is very expensive."
