Exploring the human cell in the context of a viral invasion - the battle for control of the cell, this film tells the remarkable story of a single cell - from birth to death in the front line of the eternal fight for supremacy. Inside the nucleus of a primitive cell the swapping and mixing of viral and cellular genetic material takes place. The forced mixing of genes and the survival pressure to stay one step ahead of the viral invaders has driven the evolution of life on earth. No-one knows for sure whether viruses and animal cells co-evolved or whether we have a common ancestor.