[1] The episode follows the dismissal and later readmission of the recently undead medical officer Owen Harper (Burn Gorman) to the alien-hunting team Torchwood.

The team discuss a series of energy spikes coming from the estate of Henry Parker, a reclusive collector of alien artefacts.

The energy from the Pulse is not as dangerous as originally thought; it was an alien species sending a reply to messages NASA sent into space in the 1970s, which appears as a beautiful light.

Owen walks on a footpath, looks up and spots a woman called Maggie Hopley, who is ready to jump off a roof on the anniversary of her husband's death.

Richard Briers previously played the Chief Caretaker and the voice of Kroagnon in the 1987 Seventh Doctor serial Paradise Towers.