By way of review, Limhi sent an expedition north to find Zarahemla, but instead, they found the 24 plates which Ether had hid in a conspicuous location (Mosiah 21:25-28, Ether 15:33). The Book of Ether is Moroni's abridgment of these 24 plates (Ether 1:2). When Alma speaks of the secret works of those people, he is speaking of the secret combinations which were so prevalent among the Jaredites (Ether 8).