Su Tai awakens in a dilapidated room to piercing summer sun, her head splitting from a head injury. She quickly realizes she has time-traveled into the body of a girl with the same name, a fool kept hidden by her family to avoid losing her childhood betrothal. The original Su Tai was injured during a conflict between villages over the drying Xiao Shizi River, exposing her condition to all. The Su family is poor but loving, consisting of parents Su Chunlin and Han Shi, elder brother Su Zhan, and six-year-old younger brother Su Ming. They are now facing a great drought that has lasted three years, leaving water extremely scarce. As a modern female college student who died fleeing an arranged marriage in her previous life, Su Tai finds this family far better than her original one.Soon after she recovers her senses, the Xiong family, led by Xiong Kai’s aunt Ding Shi, arrives to break off the engagement. They demand an explanation for hiding Su Tai’s foolishness. Su Chunlin and Han Shi are furious and refuse, but Xiong Kai insists he cannot support a fool. Su Tai, now lucid, advises her father to agree to the broken engagement in exchange for compensation: a bag of grain and two jars of water, to be repaid within three days. This is a practical decision, as she sees Xiong Kai is not a good person. The acceptance calms the immediate conflict, but the family is still troubled by the drought.Su Tai has a hidden advantage: a dream about a Space-Time Gate Transfer Station. In this circular space, she can sell items into an automatic trading cabinet to earn virtual coins. Accumulating fifty coins will allow her to open one of five doors representing gold, wood, water, fire, and earth. Considering the drought, the Water door is her hope. She begins collecting stones from a nearby dried-up stream, selling them to the cabinet. Ordinary stream stones yield only a few coins each, while low-quality jade pieces give slightly more. After several days of hard work, she has only over thirty coins, not enough for the Water gate.Meanwhile, the water crisis worsens. Su Chunlin and others secretly salvage the last water from the Xiao Shizi River overnight, leaving half a jar of mud in the kitchen. The next morning, villagers from upstream Ximen Village arrive, accusing Dongmen Village of stealing water. A fierce brawl erupts at the riverbank. Su Tai sees her younger brother Su Zhan being beaten by a group of half-grown boys from Ximen Village, including Xiong Dao, a relative of Xiong Kai. She rushes in with a stick and fights fiercely, knocking several of them. Just as Xiong Dao calls for more attacks, a man named Shen Yi intervenes, calling the group shameless for beating a woman. Su Tai takes advantage of the protection and continues hitting the bullies, until Su Zhan pulls her away. Xiong Dao is injured and falls, potentially seriously. The village heads arrive to calm the situation, but the tension remains high.To find a solution, the two villages decide to dig a well in a humid area of the mountains, though the cost and risk are concerns. Su Tai returns home and resolves to focus on earning more virtual coins. She guesses that larger stones might be worth more than small ones, so she turns her attention to the heavy stream stones weighing tens of kilograms. She continues her efforts to unlock the Space-Time Gate, knowing that the entire village’s survival depends on finding a reliable water source. The Su family remains supportive, and Su Tai uses her wits to protect them and seek a way out of the crisis.
