Two intervening minisodes were released. One,
The Great Detective (2012), was created for the Children in Need special. The second is
Vastra Investigates: A Christmas Prequel (2005) (which has a duplicate IMDB listing as a TV movie,
Vastra Investigates: A Christmas Prequel (2005)). The prequel segues directly into the Christmas special,
The Snowmen (2012).