The American Civil War... a time of great unrest, when fathers found themselves in conflict with their own sons and when lawlessness and slavery were rife. The Doctor, together with his companions Peri and Erimem, arrive in the middle of the conflict. The Doctor manages to cope in his own inimitable manner, but Peri -- an American -- and Erimem -- a dark-skinned Egyptian -- find themselves faced with all the bigotry and hatred that typified the war for some.