Set in the same timeline as NieR: Automata, "NieR: The Forgotten" unfolds in a desolate world, following Yuu, an android crafted by Sakamoto, the last remaining human and a former YorHa high command member. Together with 5z, a loyal floating mecha companion armed for battle, they explore ruins overrun by hostile machines, seeking surviving androids and protecting Sakamoto, humanity's last hope. Despite daunting challenges, they persist, facing treacherous terrain, powerful foes, and moments of self-discovery amid the remnants of a once-thriving civilization. Their journey becomes more than a fight for survival; it transforms into a quest of self-realization, fostering a profound familial bond as they navigate the desolation and find purpose amidst the ruins.