The episode will last for an extended 55 minutes, the longest episode of this series so far, and finishes at 9pm. Heaven Sent, penned by Steven Moffat, will air on the same day on BBC America at 9/8C.
Trapped in a world unlike any other he has seen, the Doctor faces the greatest challenge of his many lives. One final test. And he must face it alone. Pursued by the fearsome creature known only as the Veil, he must attempt the impossible. If he makes it through, Gallifrey is waiting…[Source: BBC]