"Orbiting a quiet backwater planet, the massed forces of the universe's deadliest species gather, drawn to a mysterious message that echoes out to the stars. And amongst them -- the Doctor," a synopsis said. "Rescuing Clara from a family Christmas dinner, the Time Lord and his best friend must learn what this enigmatic signal means for his own fate and that of the universe."
A promo for the program posted Monday on YouTube has been viewed more than 1.5 million times.
Peter Capaldi will be the 12th actor to play the titular Time Lord when the 50-year-old show returns next year.