Flashlight

"'Flashlight'" is the fourth episode of the tenth season of Doctor Who, set it Surrey in the 21st century where people are mysteriously disappearing with a flash of light.

Synopsis
"People just vanish! Up and away without a sign! It has the police utterly confused" - Jim McReary to the Doctor

The TARDIS lands in Surrey, and the Doctor and Christina enjoy the sights until a bizarre case of disappearances with a bright light leads them to discover a race of aliens need human hosts to rebuild their empire, much to the Doctor's chagrin.