Matryoshka

When a strange force drags the TARDIS to Earth, it's clear that the Doctor, Harry and Naomi are up against an incredibly powerful being. And when they encounter Lord Pearson, inventor of games and toys, searching for his vanished daughter... it becomes clear exactly who that being might be. Hide and seek is one of the simplest games devised by man... but in the hands of The Toymaker... it may also become the deadliest.