A Good Man Goes to War
The three characters first appear in the sixth series episode "A Good Man Goes to War." Madame Vastra (a Silurian) and Jenny Flint (a human) are a married couple. In later stories we see them living in London during the 19th century. Strax, a Sontaran, is seen in his first appearance to be acting as a nurse, caring for wounded soldiers on another planet. They are all recruited by the Eleventh Doctor to help him rescue Amy Pond. Despite the success of the effort, Strax apparently dies in the battle. He is, however, shown to be awakened by Vastra and Flint a couple of days later, in the webisode "The Battle of Demons Run: Two Days Later"; he then became their butler in the 19th century.