Mei loses her Japanese mother at age six. Growing up in suburban Surrey, she yearns to fit in, suppressing both her heritage and her growing love for her best friend Fran. Yuki leaves the Japanese countryside to pursue her dream of becoming a concert violinist in London. Lonely and far from home, she finds herself caught up in the charms of her older teacher. Haruka attempts to navigate Tokyos nightlife and all of its many vices, working as a hostess in seedy bars. She grieves a mother who hid so many secrets from her, until finally one of those secrets comes to light. Shifting between three intertwining narratives, Mongrel reveals a tangled web of isolation, desire, love, and ultimately, hope.