Gran and his crew embark on their first official quest to locate a missing archduke, only to find themselves navigating treacherous caves and a secret factory. The objective is to rescue the archduke of Valtz Duchy, a task that leads Gran and his companions to a young mage named Io. Io guides them towards a rumored hiding place, but the path is fraught with peril, including a dangerous cave system. The narrative framework appears to be a straightforward adventure, following the crew's efforts to overcome obstacles and achieve their goal.

This volume of the Granblue Fantasy manga adapts the early adventures of Gran and his crew, focusing on their first quest to find a missing archduke. The narrative introduces new characters like Io and sets up a classic adventure scenario involving exploration and mystery. As part of a larger franchise, the manga aims to provide fans with a visual representation of the world and characters they enjoy. The inclusion of designers from classic Final Fantasy titles suggests a focus on engaging storytelling and character development within a fantasy setting.