Kugan, of which the original Korean title is UJ Report, is the longest-running Korean Boys' Love serial novel of the urban fantasy genre. The serial novel started in 1999, and its chapters continue to be released in installments today. The story begins with Detective Jay Yoo in action in an uncharted city named Kugan. Jay became a cop after graduating the police academy, where he met his best friend, Vinny Monticelli, the troublemaker behind all sorts of inexplicable and mysterious accidents. Jay puts his life on the line every day, investigating critical and serious crimes happening within Kugan, on top of his daily attempt to survive his buddy Vinny, who breaks and destroys everything and anything that comes within his reach. Jay was having an ordinary day like any other when the serial killer he had arrested in a past case escaped confinement. The mad killer, who had stayed low for about three years in captivity, showed signs of coming after Jay, putting the detective in danger. Meanwhile, the clash of two giant clans of mafias dominating the city begins.