On the anniversary of last summer's brutal conflict in Gaza, film-maker Adam Wishart visits Jerusalem and rides the city's controversial new train. Only nine miles from start to finish, some hoped it could help heal divisions between Israelis and Palestinians, but as Wishart discovers, it has only deepened the sense of resentment on both sides. Travelling through the old city, he comes face to face with the battle over one of the world's holiest sites and asks, could it be the flashpoint for the start of another war?