Birth island is home to the "Chimerans", a tribe of humans who can turn into monsters. but then one day in 1991 a new nuclear bomb is tested on the island unknowing of the existence of the tribe and then after mutates their monster forms into giant monsters. 33 years later, Shin Haken is walking home from work and then suddenly blacks out. She wakes the next day in piles of city ruins with her clothes torn & blood and bullet holes in her. She gets helped by some medics and gets brought to the hospital and put in the ER. Days later, she remembers what happened after she blacked out. She turned into a giant reptilian dinosaur-lizard-thing and shot white atomic breath out of her mouth and destroyed most of her city. Then she is kidnapped by people who turn out to work for a secret government agency known as Zephyr who keep track of how many "Chimerans" are out there. She even finds out that her supposedly dead father works for them. Then she gets mad and turns into what Zephyr calls "Godzilla" again. So, Zephyr sends in Kiryu to fight her and calm her down before she completely destroys New York entirely.
