Firebreather is the story of Duncan Rosenblatt, the 16-year-old son of separated parents: Margaret, a typical suburban soccer mom and Belloc, a 120-foot fire-breathing Godzilla-type creature known as a Kaiju.

Belloc is the ruler of the Kaiju and when war broke out 16 years ago between the humans and the powerful race of monsters, it was the relationship between Margaret and Belloc that prevented massive destruction on both sides. The Kaiju disappeared and Margaret was forced to raise her child Duncan as a single mother, providing him with as normal an environment as possible.

Even though the Kaiju are gone, the world still fears these monsters, so a government agency called MEGTAF remains in place to protect humanity against their potential return. Margaret has made a deal with the agency that includes MEGTAF agent "Blitz" Barnes keeping tabs on Duncan and Margaret.

High school is tough enough as it is, so Duncas temper and scaly orange skin doesn't help him fit in. At his new school, he makes friends with outsiders Isabel and Ken and falls for the popular and stunning Jenna. But like his past schools, Duncan makes an enemy of school bully and Jenna's ex-boyfriend, Troy.

Knowing his son is coming of age, Belloc has been searching for Duncan and wants to introduce him to the world of the Kaiju, hoping that Duncan will someday take his rightful place as his heir to the throne.