Shin a poor mecanic survives through scamming people. One of those people is Jake. Jake finds out and confronts Shin. They begin a sexual relationship and very quickly Shin starts looking into who Jake really is. On the fave of it, Jake is a drug dealer working for some gang. Turns out, he is an undercover cia agent trying to dismantle that gang (the mercifuls). Right now its getting a bit difficult because Jake might blow his cover, we don't know but its going that direction. Regarding Shin and Jay's relationship, it is not toxic at all, they are obsessed with each other. Hope that helped a bit

icl it’s been so long i forgot the plot…
i can’t reread 100 chapters again
if anyone would like to quickly drop a brief summary so ik what’s going on again