Figure 17: Tsubasa & Hikaru - S01

Tsubasa Shiina is a 10-year-old girl who has just moved to Hokkaido to live with her father. At school, she is very quiet and keeps to herself around her classmates. Then one night, she sees a UFO crash in the forest near her home. She hurries to the site and finds the pilot, codenamed "D.D.", barely stable. Also there is a Maguar, a hideous alien that hatched aboard D.D.'s ship. As the Maguar is about to kill Tsubasa, an alien lifeform fuses with her body to form the Riberus battle armor Figure 17, which quickly destroys the alien. The lifeform takes the name Hikaru and becomes an identical twin of Tsubasa. Over time, Tsubasa opens up more to those around her, thanks to her new twin sister Hikaru. But with Maguar eggs scattered across Hokkaido, their ability to form Figure 17 is needed to wipe out every hatched Maguar until backup from D.D.'s home planet reaches Earth.