Scarlet Nexus is set in a world where humans have developed psionic powers. These powers have changed the world, not necessarily for the better. Lured by the alluring scent of amplified human brains, lines known as Others have descended upon the planet. Yuito Sumeragi and Kasane Randall are two members of OSF sent into battle against the invaders. As their paths intertwine throughout the course of their mission, more questions about the state of the human psyche and its power to connect with others arise.