The body of a teenage girl, bound and gagged, falls from a high-rise block, hitting the concrete in front of Nina as she cycles home.
The next day the newspaper says it was a suicide and Nina doubts her memory. She goes back to talk to the neighbours and kids from the north London estate where the girl lived. There's a man following her.
Nina is 53, unemployed, mother of two grown boys, and long term partner of a respected poet. She doesn't seem the kind of person that should be investigating a murder, but Nina hasn't been entirely honest about the kind of person she is.