"Inazuma Eleven Go vs. Danbōru Senki W" is a crossover anime film that brings together characters from the "Inazuma Eleven Go" and "Danbōru Senki W" series. The narrative centers around the sudden appearance of a mysterious entity known as the Black Mist, which begins to engulf the world, threatening both the soccer-playing protagonists of "Inazuma Eleven Go" and the LBX (Little Battler eXperience) fighters of "Danbōru Senki W." The story unfolds as the two groups of heroes, initially unaware of each other's existence, are drawn together to confront this shared threat.

The protagonists from "Inazuma Eleven Go," led by Arion Sherwind and his teammates from Raimon Middle School, are introduced as they prepare for a crucial soccer match. Meanwhile, the "Danbōru Senki W" characters, including Ban Yamano and his friends, are engaged in their own battles using advanced LBX robots. The Black Mist disrupts both worlds, causing chaos and forcing the two groups to cross paths. As the mist spreads, it becomes clear that a powerful antagonist, Professor Edgar, is behind the phenomenon, seeking to merge the two realities to create a new world under his control.

The film explores the collaboration between the soccer players and LBX fighters as they combine their unique skills to combat the Black Mist and its minions. The Raimon soccer team utilizes their soccer techniques and teamwork, while the LBX fighters rely on their mechanical prowess and strategic combat abilities. Together, they face off against Professor Edgar's forces, which include corrupted versions of familiar characters and powerful LBX units. The climax involves a high-stakes battle where the heroes must work in unison to defeat Edgar and restore balance to their worlds.

Key characters from both series play pivotal roles, with Arion Sherwind and Ban Yamano serving as the central figures who bridge the gap between their respective teams. The film emphasizes themes of unity, teamwork, and the importance of combining diverse strengths to overcome seemingly insurmountable challenges. The narrative is driven by action-packed sequences, strategic battles, and moments of camaraderie as the characters from two distinct franchises come together to save their worlds.