The Arrival

The Arrival was an event that the Governors were preparing for under the guidance of a Weeping Angel. Described as a "glorious day" by the Chair of the Governors, it was depicted in a prophetic tablet (which showed a large Weeping Angel standing over London) on the wall of Room M17 of Coal Hill Academy. (TV: The Lost)

Behind the scenes
After the cancellation of Class, the events of the Arrival were never depicted. Writer Patrick Ness mentioned on Twitter that a Weeping Angel civil war would have been included, as would a visit to their home world.