The Time of Angels  
The BBC Press Office has released the synopsis for the fourth episode of series five, The Time of Angels, written by Steven Moffat. Synopsis is below.

“Don't blink – the Weeping Angels return in the fourth episode of Doctor Who, which is written by Steven Moffat.

The Doctor, played by Matt Smith, is recruited by Father Octavian to track the last of the Angels through the terrifying Maze Of The Dead.

Meanwhile, the mysterious River Song re-enters the Doctor's life – but can he trust her?

Father Octavian is played by Iain Glen and River Song by Alex Kingston. The Doctor's companion, Amy Pond, is played by Karen Gillan.”

The Time of Angels airs on Saturday April 24th at 6.25pm on BBC One and BBC HD, and will be followed by Doctor Who Confidential on BBC Three/HD.