The Doctor and Steven materialise on an asteroid on which a peace treaty is about to be signed between humans and Omwanar. However, Space-General Robert Simmons, the only human trusted by the Omwanar, who was to sign the treaty, has just died of a heart attack. His personal assistant, Harlow, is afraid this means the war will continue, but the Doctor has an idea. The Doctor convinces Harlow and Space-Colonel Rufus Malvin to allow Steven to masquerade as Simmons, as the Omwanar probably can't tell one human from another.