"Warlords of Sigrdrifa" is set in a world where humanity faces an existential threat from mysterious, otherworldly pillars that appear across the globe, unleashing destructive creatures known as Pillars. These entities render modern weaponry ineffective, forcing humanity to rely on Valkyries—female pilots who wield ancient, divine weapons to combat the threat. The Valkyries are supported by Odin, a divine figure who grants them the power to fight, though his motives remain enigmatic.

The story centers on Miyako Muguruma, a former ace pilot who becomes disillusioned after a tragic mission results in the loss of her squad. She is reassigned to the Sigrdrifa Squadron, a ragtag group of Valkyries stationed in Norway. The squadron includes Claudia Bruford, a stoic and disciplined leader; Azuzu Komagome, a cheerful and energetic pilot; and Sonoka Sagami, a reserved and introspective member. Each character carries personal struggles and motivations, which are gradually explored as the series progresses.

The narrative unfolds as the Sigrdrifa Squadron engages in battles against the Pillars, uncovering the origins of the threat and the true nature of Odin's involvement. The Valkyries face not only external enemies but also internal conflicts, as they grapple with loss, duty, and the moral complexities of their mission. The series balances action-packed aerial combat with character-driven moments, delving into themes of sacrifice, camaraderie, and resilience.

As the story advances, the Valkyries discover that the Pillars are tied to a deeper, more sinister plan orchestrated by forces beyond their understanding. The series builds toward a climactic confrontation, where the Sigrdrifa Squadron must confront both the external threat and their own limitations to protect humanity's future. The plot maintains a steady pace, blending episodic missions with overarching narrative progression, culminating in a resolution that ties together the personal and collective struggles of the characters.