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.

Cheerful high school girl Ha-na (Lim Ju-eun) is always the first to come out and protect her introverted twin sister Doo-na (Park Ji-yeon), who has a slight limp. After Doo-na passes away in a fire, Ha-na finds that her body no longer completely belongs to herself. Doo-na's angry spirit now lives in Ha-na, giving her special powers and monstrous strength. Genius criminal psychologist Shin Ryu (Lee Seo-jin) is an expert profiler who is determined to see justice served. When he learns about Ha-na's abilities, he uses her powers to eliminate criminals that are above the law, and to plan his revenge on the man (Kim Kap-soo) who helped his family's killer go free.

Hana Yayoi (Takajo Aki) is a descendant of special family which has super human knowledge, good at information war. She has keen powers of observation to see through people's secret, and her twin brother (cast by Former D-BOYS member Endo Yuya) has over 180 IQ.

NIP CHI YUEN (Ma Steven), who works in the anti-smuggling camp, is determined to wipe out the Tau's Fort, which is the stronghold for salt smugglers. He pretends to be a down-and-out scholar. TAU SING SUET (Yeung Yi) daughter of the chief smuggler, sympathizes with YUEN and puts hiim up in the village. Later, they even become fond of each other. During an anti-smuggling operation SUET is badly hurt and has since been separated from YUEN and her family. Fortunately she is saved by WU TING HIN (Wong Ho Yin), son of salt merchant WU KIN (Kwok Fung). HIN takes her home. One day, SUET is horrified to see the dead bodies of her parent being hung on the wall of the city tower, and that the official standing on the top of the tower telling the public not to sell smuggled salt is none other than the man she misses day and night. She is heartbroken, and her love for YUEN turns into hatred that moment on.... HIN finds a job for SUET at the salt company his family runs to help her get over her unhappiness. To repay him, she devotes herself entirely to the job. As time goes by, Hin starts to fall in love with her. However his critical illness making him hesitates to express his love for her. SUET's real identity comes to light when her younger uncle reappears out of the blue. HIN, for fear that his family will report SUET, proposes to her....

Park In Soon accidentally killed another girl when she was in high school. After serving her time in prison, she tried to rebuild her life but was unsuccessful due to her criminal record. She was encouraged by her high school teacher but feeling down and out, In Soon decided that her life wasn't worth living and attempted to commit suicide by jumping off the train track. Just then she was stopped by Yoo Sang Woo, her childhood friend who had moved to Canada before the incident. Through a series of events, In Soon was reunited with her mother, the famous actress Lee Sun Young who abandoned her soon after her father passed away. Can In Soon finally begin a new life and find happiness?

Akari (Fujiwara Norika) works in a jewelry store where she is sometimes asked to attend parties as a jewelry model. She is not very happy to realize that she has been singled out not for her intelligence, but for her looks. At 29, Akari is eager to get married, but her boyfriend makes it clear that marriage is not in his plans. There was once a man in Akari's life whom she has been unable to forget. She unexpectedly meets up again with Arashi (Osawa Takao) and pulses race...