Yeon Geum-hwa is a tattoo artist and a highly sought-after one at that. Unfortunately, he learned his craft from his ex-boyfriend, an obsessive and controlling man whom Geum-hwa would love nothing more than to escape from. That opportunity arises when he gets a call about a potential client in Japan. They want to fly Geum-hwa out there to perform a cover-up for someone. While it's not explicitly stated, it's not hard to figure out that this client is part of a gang or yakuza.
It's a dangerous prospect, but if it will free Geum-hwa from his ex's influence, the danger is well worth it. So, after designing the tattoo, Geum-hwa is flown out to Japan, where he meets his client, Katamoto Seung-jae, the second son of the Katamoto family's head. Geum-hwa inadvertently ends up in the middle of a power struggle between the first son and the second son, being used as leverage by the first son when Geum-hwa and Seung-jae begin a physical relationship. While he's no longer any safer in Japan than he would be at home, Geum-hwa is hopelessly in love with Seung-jae, and while Seung-jae feels the same, he isn't willing to risk Geum-hwa's life.
Even though Geum-hwa is willing to risk everything to be with Seung-jae, Seung-jae feels compelled to let him go. Will Seung-jae be able to follow through, or will he be unable to let Geum-hwa go?