Hiljae and Advis, sons of the volcano keeper, see smoke coming from their home volcano while their father is away. They go into the forest and meet a creature called a chode who offers to help them reach the volcano. The boys and the chode travel to the volcano, where the boys must choose which hole to insert crystals into in order to stop the eruption. They successfully insert the crystals into the second hole, silencing the volcano and saving their town. When their father returns, the boys plan to tell him about their adventure and may someday become volcano keepers themselves.