And it came to pass that the Lamanites came up on the north of the hill, where a part of the army of Moroni was concealed. And as the Lamanites had passed the hill Riplah, and came into the valley, and began to cross the river Sidon, the army which was concealed on the south of the hill, which was led by a man whose name was Lehi, and he led his army forth and encircled the Lamanites about on the east in their rear. And it came to pass that the Lamanites, when they saw the Nephites coming upon them in their rear, turned them about and began to contend with the army of Lehi.