In this book, the Thea sisters travel to Alaska for a conference held by the Green Mice, who are an ecological association. The Thea Sisters consist of Nicky, Colette, Pamela, Paulina and Violet. The five of them enjoy their trip in Alaska, exploring beauty and wonderful ecosystems. Meanwhile, the Thea Sisters find out that someone has planned to disturb the ecosystem by blowing up the ice with explosives. Will the Thea Sisters be able to stop the destruction and save the ice in time? The book also includes the history of Alaska which makes it interesting and educational for the children.