Operating from the Headquarters in London’s Paternoster Row, the “Paternoster Gang” are an unlikely trio consisting of a Silurian, Madame Vastra, her human wife, Jenny, and a Sontaran called Strax, who acts as their butler. Originally brought together as part of the Eleventh Doctor’s army for the battle of Demon’s Run, Madame Vastra used resurrection technology to revive Strax after he had been killed in battle.
When a despondent Doctor considers retiring, the trio rally his spirits and help him defeat an invasion by the Great Intelligence. Along with their renowned detective work in Victorian London, the three ably assist the Doctor from time to time, even helping him through a regeneration to find his new personality as the Twelfth Doctor.
Only once do the trio find themselves at each other’s throats. When the Great Intelligence meddles with the Doctor’s time stream to alter history, Strax and Vastra no longer knew each other. When he attacks her, she shoots him dead. Fortunately Clara is able to reverse all these actions by altering the time stream herself.