This is the story of Germanus, a Roman cavalry officer, who is caught up in the greatest event of Hadrian's Wall, its invasion by the Picts and Scots in 367 AD. The barbarians occupy most of Britain until they are driven back in 369. Two years before this event Germanus was posted from Gaul to a small fort on Hadrian's Wall, Pons Aelius (Newcastle), as a punishment for sexual misdemeanours. There he falls in love with Juliona. Later he is transferred to Cilurnum fort near Corbridge, which is overcome by the Picts. Germanus escapes, and in the chaos he finds Juliona again. They marry, but Juliona is killed during the Picts' withdrawal, and Germanus overcome with grief, finally leaves Britain.