Lu Chuan, a fourth-year university student, survives on steamed buns and pickled vegetables, always believing his family is struggling financially. During a phone call, he unexpectedly discovers that his father has been sending him 30,000 yuan in monthly living expenses through an intermediary, but he has only been receiving 500 yuan. Upon investigating, he discovers that the money has been going to his father's longtime friend, Chen Guodong, whose son, Chen Mo, is Lu Chuan's roommate and enjoys a lavish lifestyle. Lu Chuan and his father gather bank transfer records and chat evidence, then pursue legal action to recover the money.