"Strike Witches: 1937 Fuso Sea Incident" is a manga series set in an alternate historical timeline where humanity faces an alien threat known as the Neuroi. The story takes place in 1937, focusing on the Fuso Sea Incident, a pivotal event in the ongoing conflict between humans and the Neuroi. The narrative centers on the 507th Joint Fighter Wing, a specialized unit of Strike Witches—young girls endowed with magical abilities and equipped with Striker Units, mechanical devices that allow them to fly and combat the Neuroi.

The protagonist, Takei Shizuka, is a skilled pilot and a member of the 507th. Her character is defined by her determination and sense of duty, as well as her struggle to balance her personal emotions with the demands of her role. The story explores her interactions with fellow witches, including the stoic and experienced Miyafuji Yoshika, who serves as a mentor figure, and the spirited but reckless Lynette Bishop. Together, they form a cohesive unit, each contributing unique skills and personalities to the team.

The plot unfolds as the 507th is deployed to investigate a sudden surge in Neuroi activity in the Fuso Sea. The incident escalates when they encounter a massive Neuroi hive, far more advanced and dangerous than any previously encountered. The witches must navigate not only the physical challenges of combat but also the psychological toll of facing an enemy that seems to adapt and evolve with each encounter. The narrative delves into themes of camaraderie, sacrifice, and the human cost of war, as the characters grapple with the realities of their mission and the personal stakes involved.

Key events include a series of intense aerial battles, strategic planning sessions, and moments of introspection as the witches confront their fears and doubts. The story also incorporates elements of world-building, providing glimpses into the alternate history and the broader context of the war against the Neuroi. The Fuso Sea Incident serves as a turning point, highlighting the resilience and resourcefulness of the Strike Witches while setting the stage for future conflicts.

The manga maintains a balance between action and character development, offering a detailed exploration of the protagonists' backgrounds and motivations. The relationships between the witches are central to the narrative, with their bonds of trust and mutual support playing a crucial role in their ability to face the Neuroi threat. The series concludes with a resolution to the immediate crisis, but leaves room for further exploration of the ongoing war and the evolving dynamics within the 507th Joint Fighter Wing.