Three boys, Takuya, Kazuki, and Dai are from Ishinowa elementary school in the sixth grade. They are actively a strong, curious, mischievous trio. They obtained a mysterious jewel's "Power Stone". They bring back Dran, the golden robot, a brave who slept within a Power Stone and they became his master. However, Prince Walter Walzac, who aims at the Power Stone, has attacked them. They then go to an adventure for searching eight Power Stones that were scattered all over the world. They now aim at El Dorado's Legendra with Goldran.