Armageddon isn't all bad. When the world ends, there will be earthquakes and tornadoes. There will be sheets of acid rain. There will be fires and floods and bolts of electricity surging out of the sun. That's the first three pages of this fourth entry in the Infinity Ring series. No one will accuse the author of holding back. R.E.M. fans may wonder if the book is adapted from "It's the End of the World as We Know It (And I Feel Fine)." But it turns out that an apocalypse was exactly what this series needed. As Sera uses the Infinity Ring to jump back and forth in time, from the end of the world to the age of the Maya, the story gains a sense of urgency that was missing from previous volumes. She has to prevent the Cataclysm, and her friend Riq may wink out of existence altogether. A time paradox means that his parents may never have met. These are the dangers of time travel. Like the previous volumes, this book suffers from terrible dialogue and implausible plot twists, but it also includes the funniest line in the series, a joke about TriSQuit crackers. (You had to be there.) Fans of the series will already be hooked, but even more skeptical readers may be a little curious what happens next. (Science fiction. 8-12)]] Copyright Kirkus Reviews, used with permission.

The fourth Infinity Ring episode sends time-traveling youths Sera, Dak, and Riq first back to the early days of the Mayan civilization and then forward 800 years to witness the fiery destruction of its native culture by the Spaniards. Carrying out their mission to save an ancient codex entails narrow squeaks aplenty and clashes with the archenemy, Time Wardens. Historical background and games that link this volume with previous and future ones are available on a dedicated website. Fans will know what to expect; new readers had best start at the beginning to catch up on the characters and conflicts.--Peters, John Copyright 2010 Booklist

Time travelers Dak, Sera, and Riq visit the American South in 1850 to restore the Underground Railroad (Trap), then visit ancient Mexico to save a Mayan codex from destruction (Curse). While Trap treads familiar ground in its exploration of American slavery, Curse, with nuance and sincerity, depicts the less-familiar Spanish eradication of Mayan cultural artifacts. (c) Copyright 2013. The Horn Book, Inc., a wholly owned subsidiary of Media Source, Inc. No redistribution permitted.