"Figure 17" is a science fiction anime series that blends elements of slice-of-life storytelling with action and emotional depth. The narrative centers on Tsubasa Shiina, a reserved and introverted 10-year-old girl who moves with her father to rural Hokkaido following her mother's death. Struggling to adjust to her new environment, Tsubasa's life takes an unexpected turn when she encounters an alien life form named DD. During this encounter, Tsubasa inadvertently bonds with DD, gaining the ability to transform into a powerful being known as Figure 17. This transformation grants her enhanced strength and agility, which she must use to protect Earth from hostile alien creatures called Zoa.

As Tsubasa navigates her dual life as a schoolgirl and a protector of humanity, she forms a close bond with Hikaru, a girl who resembles her but possesses a more outgoing and confident personality. Hikaru is revealed to be a manifestation of Tsubasa's inner self, created through her connection with DD. Together, they face the challenges of battling the Zoa while also dealing with the everyday struggles of growing up, such as making friends, coping with loss, and finding their place in the world. The series explores themes of identity, resilience, and the importance of human connections, as Tsubasa learns to balance her responsibilities as Figure 17 with her personal growth.

The plot unfolds over 13 episodes, with a mix of episodic battles against the Zoa and longer arcs that delve into Tsubasa's emotional journey. The series maintains a steady pace, allowing for character development and world-building while keeping the stakes high with the ongoing alien threat. The rural setting of Hokkaido provides a serene backdrop that contrasts with the intense action sequences, emphasizing the duality of Tsubasa's life. Through its narrative, "Figure 17" offers a thoughtful exploration of its protagonist's inner struggles and the broader implications of her role as a defender of Earth.