To find help, one of the brothers travells to the Snoring Dragon Inn and offers the Dragon Hunters a large amount of gold should they defeat the dragon. As the brother claims that the dragon is merely five feet high, Gwizdo expects the task to be fairly easy. Having arrived at the Isle of Mist, Gwizdo and Lian Chu wait on the bridge for the beast to arrive. Eventually, the Mist-Bomber advances from the mist, however it is far more larger than the brother's claimed. Gwizdo realises that the brother at the Inn was measuring in "Old Feet", not having been aware of a past decree that changed the units of measurement. Now facing a far biger Dragon than expected, Gwizdo and the brothers run back to the monastery, leaving Lian Chu to fend of the giant dragon. Lian Chu is also forced to flee back, just so managing to escape the beast.
Back at the monastery, Gwizdo angrily yells at the brothers for failing to give the correct size. He threatens to leave, only giving in when the brothers reveal that they cannot pay the Dragon Hunters because all their gold is stored on the Isle of Mist.
Together, Gwizdo and Lian Chu device a new plan to defeat the dragon. They take the cloaks of the brothers and Lian Chu sows together a giant parachute. Lian Chu enters the bridge to pass as bait for the Mist-Bomber and Gwizdo and Hector manage to trap the beast inside the sack. However, the dragon breaks free and pursues the gyrocopter. To get faster, Hector throws off balast, one thing being a stinking cheese the brothers manufacture in their monastery. After eating the cheese, the Mist-Bomber faints from the bad taste and passes out, crashing into the Isle of Mist.
The brothers then reveal their true motivation; the river on the island is a fountain of youth. After drinking from it, they get younger but then attack Gwizdo and Lian Chu, intending to kill them because they know to much. However, the Dragon Hunters escape in their gyrocopter and the brothers can only watch as they fly off. They are then shocked when they see that the Mist-Bomber regains consciousness and run back to their monastery.
Before the credits roll, the Mist-Bomber can be seen flying past the Snoring Dragon Inn.