Kwon Yeon-woo is a thirty year old low-level civil servant who works in a district office; quite innocent for his age, he has been on numerous blind dates in an unsuccessful bid to find a wife. After moving into a new place, he begins to encounter a high school girl, Soo-yeong, on his way to work every morning, and she begins to develop feelings for him. Meanwhile, Kang Sook has just started working at the district office straight out of high school, and falls head over heels for older woman Kwon Ha-kyeong.

Because of her motion sickness, a 68-year-old mother decides to embark on a four-day walking trip to attend her youngest daughter's wedding.

In a thrilling story that mixes a love triangle with mob drama, RUN 2 U focuses on the lives of three troubled young people. Hiroshi, a club singer, finds himself in trouble with the Yakuza and decides to run to Korea, along with his friend Tsuyoshi. Upon their arrival, they meet alluring lounge singer Kyung. Hiroshi and Kyung's love of music draws them closer, but it also invokes tremendous jealously from Tsuyoshi. Eventually, the Yakuza closes in, leaving them to both save their lives and resolve their romantic feelings.

Hyun-jae, a 16-year-old escaping her abusive father, manipulates Hae-in, a woman searching for her missing daughter, into taking her in as a replacement. Over the summer, Hyun-jae bonds with Hae-in, finding peace through her love for singing, but becomes obsessed with becoming Hae-in's new daughter. When Hae-in learns her missing daughter may have been found, Hyun-jae, despite her fears, makes a selfless decision to accompany her, realizing she can't replace Yun-seul.

A unemployed father, due to his laziness, is supported by his wife. Their daughter decides to put their lazy dad up for rent on a secondhand site.

Film director In-seong and scriptwriter Yun-ju have been seeing each other secretly. Min-a, In-seong’s ex-girlfriend, is now living in Japan, so when she decides to come to Korea to gather some news material, she makes contact with him and they arrange to go to Gangreung together. Yun-ju is kept in the dark about this. In the country cottage in Gangreung, In-seong tries to win Min-a back, but she doesn’t want him and so she leaves.

Hyeong-Ju is a gang member. He begins to follow a woman. The woman is the wife of a prosecutor investigating his gang. The woman was also Hyeong-Ju's teacher when he was younger and he liked her at the time. Hyeong-Ju still has feelings for her.

Upon getting out of prison, Deok-Bae meets his old buddy Dal-soo, who owns a restaurant. These two have never succeeded in life, and are constantly in and out of prison. Two others who happen to be in the same boat as Deok-Bae and Dal-Soo are ex-convicts. They have threatened to commit suicide unless traffic and unemployment issues are resolved. They are also unlucky enough to have been spotted at the scene of a crime. While these four are making big plans for their first success, the city becomes wrapped up in a serial murder case. In the meantime, an investigating team of veteran cops is formed in order to solve this case.

On her way home, Sun-jung discovers that the earbuds she picked up on the subway are actually part of a robot from the future. The robot reveals to Sun-jung that her daughter will become a key figure in an anti-technology movement in the future, and threatens her to make her daughter use a smartphone in order to raise her as an ordinary child.