Following clues provided by the secretive Reddimus Society, the four Alden siblings travel to a dingo sanctuary in Australia and to Shakleton's hut in Antarctica to deliver the fifth and sixth artifacts, and then they work to unmask the traitor traveling with them.

The author captures the icy beauty of Antarctica and the wonders of a penguin family that thrives there.

"All day long the penguin colony plays and plays, and when the sun goes down and the night grows cold and dark, they squeeze and squish together ('penguin huddle!') to stay warm and snug. But one morning, after a freezing gale, the penguins find themselves stuck, frozen together like a giant penguin ice pop. When no one in the Antarctic can unstick them ('penguin muddle!'), Pipsqueak, the smallest penguin of all, leads his fellows out of their snowy...