Watch Firebreather for Free: How to Stream the Movie Online at 123Movies. . It's not easy being a teen like Duncan. His mom wants him to pay more attention to his homework, while his dad - a 120-foot-tall monster known as a Kaiju - wants him to become the next King of All Monsters. When these worlds collide, Duncan must use his human wits and his Kaiju powers - including super strength, agility and the ability to breathe fire - to protect his family and friends from a giant monster rampage.