Frax and Wilt are searching for Wilt's quirky physicist father, missing without a trace.Sparrow is looking for her archaeologist mentor, and the mysterious mug-like artifact found at her Native American dig site.The secret government lab where Maud's mother worked has been vaporized during experiments with a similar artifact.Ruthless agents are after another one.The four teens discover the mug in a hidden fallout shelter under Wilt's garage, controlling a much larger replica - a portal to somewhere else... and the lost scientists?But the agents arrive, and mount a serious attack on the heavy shelter door. Trapped, the teens escape the only way they can. There's no cell service on the other side, but they see familiar plants and animals and know they can't be too far from home.Boy, are they ever wrong!