The Doctor is visiting Sarah at Christmas. She is currently taking care of her granddaughter Lily. Lily has Autistic Spectrum Disorder, and it is all Sarah can do to keep Lily happy enough to keep her out of trouble. The three attend the church service, during which the congregation sings Christmas carols. Lily loves music, and sits still to listen. When the singing is over, she runs for the door instead of heading for the refreshments, and the Doctor and Sarah follow her.