In a world where emotions are tangible entities harvested from people, you are an Emotion Engineer, responsible for shaping and selling feelings to the highest bidders. When a rare and enigmatic heart—containing a mix of joy, sorrow, and rage—mysteriously appears on the black market, you are pulled into a high-stakes game involving rival Emotion Engineers, clients with twisted desires, and an underground syndicate. Navigate through moral choices that impact your character's emotional stability and the hearts of others, all while unraveling the secrets behind the heart's origin. The deeper you delve, the more you discover that to truly understand feelings, you might just have to experience them yourself.