College student Ergou worries about tuition fees, but his sister-in-law insists on selling everything to support his education. By chance, he obtains a mysterious thumb ring containing the spirit of Shennong, which can make wild sweet potatoes grow larger and sweeter quickly. He then makes money by selling these special sweet potatoes. He stands up to protect his sister-in-law from harassment by the village chief's son, rescues Xiaohui, the village doctor, from being pestered by ruffians, and after striking a supply deal with Sister Yu, he faces a return crisis caused by poor quality sweet potatoes from others. Amidst the lively village life and continuous challenges, Ergou, relying on his magical thumb ring and kind heart, accumulates funds for his studies while protecting those around him.
