"Sakugan" is set in a dystopian future where humanity resides in an underground labyrinth known as the Labyrinth. The Labyrinth is a vast, dangerous network of tunnels filled with hostile creatures and treacherous terrain. To navigate and map these uncharted territories, individuals known as Markers undertake perilous expeditions. The story centers on a young, precocious girl named Memempu and her father, Gagumber, a former Marker who now works as a mechanic.

Memempu, despite her age, is a brilliant inventor with a dream of becoming a Marker herself. Her father, Gagumber, is initially reluctant to support her ambitions due to the inherent dangers of the Labyrinth. However, when Memempu discovers a mysterious signal from a distant area of the Labyrinth, she becomes determined to investigate its source. Gagumber, realizing he cannot dissuade her, decides to accompany her on the journey to ensure her safety.

The duo embarks on a perilous adventure through the Labyrinth, encountering various challenges, including hostile creatures, rival Markers, and the harsh environment itself. Along the way, they uncover secrets about the Labyrinth's origins and the fate of humanity. The relationship between Memempu and Gagumber evolves as they face these trials, with Gagumber gradually coming to terms with his daughter's independence and determination.

The narrative explores themes of exploration, familial bonds, and the resilience of the human spirit in the face of adversity. The dynamic between Memempu and Gagumber serves as the emotional core of the series, highlighting their growth as individuals and as a family unit. The Labyrinth itself is a character of sorts, with its mysteries and dangers shaping the journey and the characters' development.

As the story progresses, Memempu and Gagumber encounter other Markers and survivors, each with their own motivations and backstories. These interactions add depth to the world-building and provide additional context for the challenges faced by those living in the Labyrinth. The series balances action, adventure, and emotional moments, creating a compelling narrative that keeps viewers engaged.

In summary, "Sakugan" is a story of exploration and discovery, driven by the bond between a father and daughter as they navigate a treacherous and enigmatic world. The series combines elements of science fiction, adventure, and drama, offering a rich and immersive experience for viewers.