Birdy the Mighty Decode  

 鉄腕バーディー 

Tsutomu Senkawa is an average high school kid who is busy studying for his senior entrance exams. Tsutomu goes out for some fresh air, after a hard day's work studying for a big test, when he runs into a guy fleeing from a pretty young lady. The pursued man is actually an interplanetary criminal on the run from a Federation agent called Birdy Cephon Altera. Caught in the midst of this chase, Tsutomu gets thrown by the man at Birdy, which kills Tsutomu. Fortunately for Tsutomu, there is a way to keep him alive, although it comes at the price of discarding his body. He ends up merged into Birdy's body.

Birdy the Mighty Decode 02  
 鉄腕バーディー  02

Birdy and Tsutomu are still co-existing in the same body, as Birdy continues her duties as Federation Investigator and celebrity persona, and Tsutomu seeks to balance them with his normal everyday life. When a criminal group connected to the Ryunka incident escape from custody, hiding themselves and their alien identities on Earth, Birdy and Tsutomu are thrown back into action. It seems, however, that there are other forces involved, as well as old faces, which give Birdy time to reflect on the past, and the people that influenced her.