What is the difference between friendship and love? Or between neutrality and commitment? Gustav Perle grows up in a small town in ‘neutral’ Switzerland, where the horrors of the Second World War seem a distant echo. But Gustav’s father has mysteriously died, and his adored mother Emilie is strangely cold and indifferent to him. Gustav’s childhood is spent in lonely isolation, his only toy a tin train with painted passengers staring blankly from the carriage windows.