Monochromatic people (known as 'Monos) live in a world where they are unable to see colour and therefore view their surroundings through varying shades of grey, black and white. However, every Mono has a fated person (known as a 'Probe') who is able to trigger their grey-scale world into colour, inducing what is termed a 'Colour Rush'. Yeon Woo is a Mono. He’s aware that other colours do exist but has never experienced them for himself, nor is he interested in doing so. However, Yeon Woo’s life is forever changed when he meets Yoo Han, his Probe, and experiences his first Colour Rush. Terrified that he'll be obsessed with Yoo Han because of Yoo Han's ability to make him see colour, Yeon Woo tries desperately to avoid Yoo Han—but why does Yoo Han insist on drawing close to him?

Choi Yeon Woo is a high school student and a “mono” who sees the world only in dull, lifeless black and white. But for every mono, there is a “probe” – a kind of soulmate who allows the mono to see the world in vivid color. Yeon Woo’s probe was a boy named Yoo Han, and the two developed a beautiful friendship that blossomed into romance. But as their relationship intensified, mysterious goings-on suddenly got very unpleasant for Yeon Woo, who eventually found that Yoo Han had disappeared, with his mother also vanishing. Yeon Woo vows to do whatever it takes to track down his “probe” and his mother. A classmate named Se Hyun learns of Yeon Woo’s quest and resolves to help and protect him – as a close friendship develops between the two students. But Se Hyun hides a secret, and Yeon Woo could be about to discover the truth.

Kim Sung-Joon (Park Si-Hoo) worked as a pilot, but after becoming in deaf in his right ear he has worked on the ground. He becomes desperate. Kim Sung-Joon then meets Eun-Hong (Yoon Eun-Hye) on a blind date. Even though he doesn't love her, he gets married to Eun-Hong. After their marriage, Sung-Joon treats Eun-Hong with indifference. Suddenly, Eun-Hong dies. Kim Sung-Joon soon learns for the first time about her real heart and her first love. Holding Eun-Hong's urn, he seeks out her first love.

Three elite North Korean sleeper agents live under cover for so long that they believe their cover stories are their real identities. They are shocked when they are ordered to kill one another or face death at the hands of an elite hit team.

A highschool kid is bullied for putting lipstick on himself in a bathroom. As he dries his clothes in the laundry, he meets a mysterious girl.

Ji-wook is a virile detective with a reputation, but deep down in his heart, he always considered himself as a woman and finally decides to get a transsexual operation. However, his plan falls apart as vicious gang members start their revenge on him.