Ji Hyun was proud to be the only employee who was good at playing office politics until her rival Hye In joins the company to work on a short-term project. Hye In outclasses Ji Hyun in every way, including physical beauty and track record. It's a matter of course that she steals the spotlight from Ji Hyun, especially the attention from Senior Direction Byun.

Assistant Manager Park Seong Eun is glad to have Hye In in her team because there's finally someone who can drive Ji Hyun nuts. However, it looks like Hye In has feelings for her boyfriend Jin Ho?! As a result, Ji Hyun and Seong Eun form a new alliance to drive out the fox that has invaded their team.

Meanwhile, another couple, Sa Ra and Kyung Jun, face their own crisis. It's because of the delivery man who frequently drops by the office. Kyung Jun, who is quick-witted, keeps a close eye on Sa Ra and the delivery man who seems to have a strange chemistry going on. The advent of new characters (Project Manager Hye In & delivery man) unfolds an even more nerve-racking office tale.

This is a crime story bank staff. An ordinary timid man, when he needs to face the pressures of life, the instinct of greed to lure him into an irreversible step by step way of crime.

The fourth season will show stories that everyone has experienced not only of love, but also enlistment, job hunting, and new human relationships.

Liu Mei Li (Jiang Meng Jie) is a naive and ambitious girl who has a dream. Her dream is to become an internationally renowned designer and the first step she takes is going on China's "Dream" fashion show. Although things did not turn out well, she called attention to another pressing matter- that is her desire to find her long lost sister. Refusing to give up her dream of becoming a designer, she tries to find a job and meets the company's general manager, Zhou Xuan (Yao Yuan Hao). Both of them are tangled in a complicated love-hate relationship. Xie Jing Hua (Liu Yi Han) is Mei Li's best childhood friend but she works in the opposing company, Tian Yi. Jing Hua has unrequited love for the company president's son, Ye Guang Yi (Chi Shuai). However, he is in love with a mysterious woman named Xue Li, who seems to be connected to Zhou Xuan. Mei Li gets trapped within the battles going on between her work life and her social life. Despite all the trouble brewing up, Mei Li maintains an optimistic view, holds onto her dreams, and extends this warmth to the people around her, like a diamond shining in the dark.

Shinichiro Kosaka is a detective at the Tokyo Metropolitan Police Department. He has worked hard to become the chief of the first investigation division, but he makes a mistake. Due to his mistake, he is demoted to a police station. There, he meets detectives, who may have fewer skills, but are determined to solve cases.

Yen was sold to be a slave to Khun Ying, Praya Sihayotin's first wife. Praya Sihayotin had 3 wives, but none had children, so he took Yen to be his fourth wife, with the blessing of Khun Ying. Yen became pregnant, and soon after, so did Khun Ying. While Praya Sihayotin was away, they both gave birth, but Khun Ying's infant boy was stillborn, so they agreed to secretly give Yen's infant daughter to Khun Ying as her own. The third wife was jealous of Yen and caused problems for her, leading JPraya Sihayotin to strip Yen of her title, and return her to be a slave. As her daughter grows up spoiled by Khun Ying, Yen suffers as a slave.