The Doctor and Donna enter a world of terror inside an abandoned library. They're given only one warning: 'Count the shadows'. CAST: David Tennant, Catherine Tate

Press Release:
One hundred years ago, the Universe's greatest library was sealed off with only a cryptic warning as explanation: "Count the shadows." However, it now appears that the shadows are on the move again.

The Doctor (David Tennant) and Donna (Catherine Tate) must uncover the terrible truth behind the Nodes and the horrifying Data Ghost to uncover the Library's secret.

PRODUCTION DETAILS:
A BBC Wales production. Executive Producers Russell T Davies and Julie Gardiner. Written by Steven Moffat. Director: Euros Lyn; Episode Producer: Phil Collinson