An impetuous Federation Space Police Officer who tends to act before she thinks, Birdy Cephon Altera is a genetically engineered super-solider whose body is also augmented with an array of devices, and weapons, she also has the use of various weapons, a space ship and robot side-kick.
During one of her missions, which takes her to Earth, she accidentally kills high school student Tsutomu Senkawa and has to fuse with him in order to keep him alive while his body is being rebuilt by her advanced technology.
From time to time Tsutomu’s body disappears so Birdy can emerge and battle various aliens who come to Earth with malevolence intent.
Eventually Tsutomu and Birdy are able to communicate with each other while they’re body is the one everyone sees, with Tsutomu even proving useful in her investigations conserving aliens who want to enslave Earth and turn the population into monsters under their control.
Tsutomu’s and Birdy’s life’s are sometimes complicated by Tsutomu finding himself in control of Birdy’s body during battles, and Birdy having to run his during his normal day to day existence at school.