Watt Sears, a former peerless Mechsteel pilot known as a Steelrider, is now nearing forty and living a quiet life as a humble station employee in a frontier town. Despite the pleas of his boss and the local lord to return to active duty hunting monsters, Watt prefers to support the new generation of pilots from behind the scenes. His peaceful existence is shattered when a sixteen-year-old girl named Anna arrives, claiming to be his long-lost daughter from a bygone romance.

The setting is a fantasy world where giant mechanical suits called Mechsteels are piloted by elite warriors known as Steelriders. The kingdom of Ogdenn is on the brink of a succession crisis, and Anna has sought out her father to help her navigate this dangerous political turmoil. Watt immediately resolves to protect her, and as assailants descend on the town, he is forced to reclaim his old skills and his Mechsteel partner, Lord Gryphon, to safeguard his newfound family and his post.

The early narrative arc begins with Watt adjusting to his role as a father figure and protector, facing off against arrogant nobles who underestimate him. The conflict escalates when a shadowy scheme forces him to travel to the capital after seventeen years away to seek support from an old friend. Upon arriving, he finds the city changed and discovers he has been placed on the wanted list for treason against the royal family, making him a fugitive in his former home. This leads into a not-so-bloodless battle for the throne, culminating in Anna taking her rightful place as the new queen of Ogdenn.

Following this, the second major arc sees Watt and Queen Anna trying to adjust to their new roles. Months after the battle for the throne, they are summoned to Corona Senatus, an international congress of crowns, where they face a new kind of conflict involving political intrigue and suitors seeking Anna’s hand in marriage, forcing Watt to confront new challenges from his past.