

An English teacher begins to hear a low humming sound that no one else around her can hear.
Jordan Tannahill
BBC One

1. Episode 1
When Claire starts hearing an incessant rumbling sound, no-one seems able to help – until her student Kyle claims to also hear the noise.

2. Episode 2
Claire and Kyle discover a group of other people who not only can hear the hum but want to embrace it. However, Kyle's mother finds out about their meetings.

3. Episode 3
Unable to experience the hum the way the others can, and increasingly guilty about her relationship with Kyle, Claire has a crisis.

4. Episode 4
Claire finally loses herself in the hum as the outside world closes in on the group. One last group session ends in tragedy.

Rebecca Hall
Claire

Ollie West
Kyle

Prasanna Puwanarajah
Paul

Mia Tharia
Ashley

Niamh McCann
Siobhan