Federation investigator Birdy chases the space criminal Geega through space to Earth, where he hides in the entertainment industry under a human disguise. Birdy goes undercover herself, posing as famous model “Arita Shion” that often uses a ‘space girl’ look. A male student, Senkawa, stumbles upon a fight between the two one night in an abandoned building only to be severed in half as he is used as a shield by Geega against Birdy. Birdy heals him from imminent death in some fashion- but Senkawas body, and life, are now changed and permanently linked to Birdy.
This is a late adaptation of a really old story (1985) that was droup out...
It's a a really interesting anime, with a lot of action&fighting!
The science-fiction theme is really indulge in this anime, with makes the fighting parts really cool, and captive to the eye :p
There's also some comedy, but really low, with is a bit sad, since the theme (2minds in 1 body), could make a lot of "gags" xD
But this is a very interesting story nonetheless...and you'll certainly enjoy it!
There's also a set of 4 OVA, that tells a similar story, with the same characters, but in others circunstances...so if you liked watching Tetsuwan Birdy Decode 1&2, look for those OVA's too ;)