Nine suicides, One cult, No leader

Nine people arrive one night on Chelsea Bridge. They've never met. But, at the same time, they leap to their deaths. Each of them received a letter in the post that morning, a pre-written suicide note, and a page containing only four words: Nothing important happened today.

That is how they knew they had been chosen to become a part of The People of Choice: a mysterious suicide cult whose members have no knowledge of one another. Thirty-two people on a train witness the event. Two of them will be next. By the morning, People of Choice are appearing around the globe. It becomes a movement.

A social-media page that has lain dormant for four years suddenly has thousands of followers. The police are under pressure to find a link between the cult members, to locate a leader that does not seem to exist.

But how do you stop a cult when people do not know they are members?