I've been watching NuWho for the first time on Netflix and I've just finished series 5 but for some reason Netflix doesn't have A Christmas Carol. My local library has it but there is a wait so I'm just going to skip to series 6 and come back to it later, so I'm wondering if anything happens that I need to know for series 6. I'm looking for just the stuff i need to know for series 6 to make sense with hopefully little spoilers for the episode. Thanks.