It may sound so simple in it's premise, but it's executed so perfectly, and so delicately layered within the script, that this becomes a true gem of the show!

This develops the character and relationship between the Doctor and Martha so well, really lending to the setting and tension that is built between the pair. The character work for the Doctor, giving him a chance to discuss Gallifrey is so poignant, and sets his role as last of the Time Lords with brilliant groundwork for the rest of the season too.

Throughout the script, layers are added to consider drugs and their effects, as well as the importance of faith, which are handled so well too.

Simply stunning.