Geronimo's adventurous sister Thea narrates this tale packed with action, mystery, and friendship! In this fabumouse adventure, the Thea Sisters head to Alaska, where they're attending a conference held by an important ecological association. Their host and his family are native Alaskans who show the mouselings their favorite games and activities. But soon there's trouble--the Thea Sisters discover that someone is upsetting the ecosystem by blowing up the ice with explosives! Can the Thea Sisters figure out what's going on and stop the destruction before it's too late?