Flesh and Stone
Writer Steven Moffat came up with the concept for "The Time of Angels" and "Flesh and Stone" when he was thinking of the worst possible situations to be in with the Weeping Angels and thought of the inability to see. His first idea was blindness, though this developed into the situation that Amy ends up in. Moffat designed the two-part story to be a more action-oriented sequel to "Blink", an episode he wrote for the third series that introduced the Weeping Angels. He was inspired by the relationship between the film "Alien" and its sequel, "Aliens", which he referred to as "the best conceived movie sequel ever", describing it as being more "highly coloured" as opposed to "Alien" more low-key tone. He also intended for the Angels to have a plan that could become "almost like a war", in contrast to the way they were struggling to survive in "Blink". The title "Flesh and Stone" was suggested by Moffat's son.