Mexico. What comes to mind the moment its name is spoken? Iconic dishes such as tacos, spicy roasted corn, or grilled cactus? The sound of mariachi rising with the distinctive sombrero dance? Or perhaps the image of cowboys skilled in guiding their steeds?

Mexico holds far more than that. Countless ancient sites stand as traces of the culture of one of the most enigmatic peoples in the world, the Aztec.

Ren, a vlogger who pursues stories hidden within ancient ruins, brings his high school aged sister, Lia, on a holiday trip to Mexico. What begins as a simple journey of leisure turns grim when Lia's careless act awakens something that should have remained untouched.

Beneath the black sun that hangs in the sky, they must carve their own escape from the realm of spirits, walking its depths and confronting the sins they have committed before the sovereign of the spirit world in Aztec belief, Mictlantecuhtli.