4×04 The Time of the Angels: Part One of Two. A clue left in a museum in the far future brings the Doctor back into the orbit of the enigmatic River Song. This time, she’s chasing a Weeping Angel to the planet Alfava Metraxis. It should be a simple containment mission. After all, how hard could it be to find one angel statue in the last graveyard of the extinct Aplan race? But why has the Angel brought them here? And why do River’s soldier companions keep referring to her as “the prisoner”? And what’s in Sammy’s eye?