Monochromatic people (known as 'Mono's) live in a world where they are not able to see colours and therefore view their surroundings through varying shades of grey, black and white. However, every Mono has a fated person (known as 'Probe's) who is able to trigger their grey-scale world into colour, inducing what is termed as a 'Colour Rush'. Yeon Woo is a Mono. He’s aware that other colours do exist but has never experienced them for himself, nor was 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 would be obsessed with Yoo Han because of Yoo Han's ability to make him see colours, Yeon Woo tries to avoid Yoo Han, but why does Yoo Han insist on drawing close to him? (Source: MyDramaList) ~~ Adapted from the web novel "Color Rush" (컬러 러쉬) by Se Sang (세상).