For those willing and desperate enough, demons offer a trade of power for half of your soul. Those who agree to this trade become halfsouls, but also become targets of the Halfsoul Extermination Association (HSEA).

Following the journey of four individuals hired by HSEA, Zach is finding it hard to adjust to life ever since he ran from the HSEA and his parents, who run the organisation. Now, Zach must learn to draw the line that separates him from his parents, the fine line between love and safety, and from guilt to empowerment. Despite his sense of solitude, Zach is not as alone as he thinks. Halfsoul explores what it means to lose a part of yourself and how to get it back.