The Eleventh Doctor (Matt Smith) must save the crew of a crashing space liner by changing the heart of a miserly old human, Kazran Sardick (Michael Gambon). To do this, he travels back into Kazran's past, encountering a young Kazran and a singing alien named Abigail (Katherine Jenkins). The Doctor must convince the cynical adult Kazran to embrace joy and generosity to save everyone.

The episode was generally well-received by critics and audiences, with praise for its emotional depth, performances, and creative retelling of a classic story. It was seen as a successful blend of festive cheer and the show's characteristic sci-fi adventure.

• Praised for its heartwarming story and Matt Smith's energetic performance.
• Michael Gambon's portrayal of the miserly Kazran Sardick was a standout.
• The musical elements, particularly Katherine Jenkins's performance, were noted as a unique and effective addition.

Google audience: Viewers found the episode to be a touching and Christmassy adventure, with many highlighting the emotional core of the story and the performances of the main cast. It's often cited as a favorite modern Doctor Who Christmas special.

Nominated for a Hugo Award for Best Dramatic Presentation, Short Form.

Katherine Jenkins, a real-life opera singer, was cast specifically for her vocal talents and her performance as Abigail was largely sung live during filming.