Doctor Xiao Yan came to the emergency department of Tongshan Hospital with the pain of losing her fiancé Lin Zhiyuan. Together with doctor Bai Zhu, they used their superb medical skills to treat critically ill patients one after another in the newly established EICU (Emergency Intensive Care Unit). During the day and night medical work, the two opened up their hearts and found each other's similarities and shining points, and finally let go of their obsessions and prejudices. The doctors in the emergency department were touched by the life stories and emotional stories of the patients, and experienced the test of life and the torture of human nature together. Everyone overcame their differences, overcame all difficulties and tried their best to defend the last door in the battle to save life.