After overhearing an older boy in the locker room telling of great fishing ponds in a canyon, two young boys set out to find where the canyon is located. They discover that it is in the mountains 15 miles away and the only way they can get there is by riding down a river on horseback. They also learn that the property is owned by an old man that does not want anybody on his land. Being the way most boys are, young and stupid, they decided to go anyway. But in their innocent search for fishing ponds they stumble across a lost treasure in a cave and suddenly their lives become really complicated.