In 1988, GDR border officer Ralle Pietzsch (Thorsten Merten) receives the key to a highly secret tunnel under the border from a dying Stasi leader. But instead of handing it over as promised, he wants to fulfil his son's most fervent birthday wish and give him a magic cube. However, this only exists in the western part of the (fictitious) Upper Franconian-Thuringian town of "Sedwitz". Actually, Ralle only wants to go to the West for a short time, but then he meets the notoriously guileless BGS official Hubsi (Stephan Zinner), the enterprising innkeeper Franz Haueisen (Hannes Ringlstetter) and the pretty teacher Astrid (Judith Richter) - and before he knows it, Ralle finds himself in a web of smuggling, corruption and secret service activities.