El Capitan had once been a volcano, but it had been extinct for as long as any records could reveal. The crater in the natural basin had taken the name of the mountain, El Capitan. The rain had been falling for many days with intermittent thunder, and for several days the Lone Ranger had been camped in the sheltering overhang on El Capitan's gently sloping side, awaiting his faithful Indian companion, Tonto. As the hoofbeats of an approaching horse sounded above the heavy rain, the masked man rose to his feet to welcome his friend, who had arrived with grave news. The Indians suspected that the El Capitan lake was about to spill over the top of the basin into the valley below...