Chang Sen, an emergency room doctor, wakes up to find himself in the body of a ten-year-old boy in the household of a famous Ming Dynasty general stationed on the frontier. Carrying the memories and medical knowledge of his previous life, he realizes that serious dangers lurk within the military camp and that his family's safety is also at stake. No one believes a child's words, so he uses his medical skills to save a military instructor suffering from heatstroke and carefully writes down methods for preventing heatstroke and recovering from exhaustion in the army, hoping to protect his loved ones before disaster strikes. Little by little, he puts his healing abilities to use for those around him, asking only that his family can remain safe and together through these turbulent times.