The rigorous hydraulic engineer Da Yu moves into a shared apartment, but encounters a pipe network crisis caused by roommates randomly dumping cat litter and taking overtime baths. To restore living order, he uses fluid mechanics knowledge to launch a hardcore renovation, not only unclogging pipelines with professional technology, but also formulating strict rules to correct everyone's bad habits. As the shared apartment's water ecology returns to perfection, this experience is drawn into a comic and unexpectedly blows up across the internet. Facing massive water leakage pleas from netizens, Da Yu leads his roommates to form a task force and officially sets out, starting a wonderful journey of saving the city's water nightmare.