Charles, Louis, and Guillaume are three friends who live together as roommates in the same house, where they spend all of their free time still playing the same Farador campaign they began as teenagers; their other friend Paul has recently moved out of the house and abandoned the game to live with his girlfriend. When Charles's sister Kim, who has recently broken up with her longtime Belgian boyfriend Tom after realizing that she might be a lesbian, moves into Paul's vacated room, her presence, and her determination to push her brother to finally take the plunge on his unrealized ambition to write and publish an erotic fantasy novel, upset the group dynamics and force them to make one last push to finally reach the Castle of Farador and end the game.

Ngabo, an under-pressure cook's helper, and Mike, a zealous neo-Nazi, go through the same difficult day on the streets of Old Quebec without knowing each other. One is consumed by exhaustion, the other by anger. Through their respective solitude, Monochrome explores the invisible tensions, buried wounds and unexpected reflections that the city can reveal. A psychological thriller about the fear of the other and the mirages of the self.