The Brighton to London line. The 07:44 train. Carriages packed with commuters.

A woman applies her make-up. Another occupies her time observing the people around her. A husband and wife share an affectionate gesture. Further along, a woman flicks through a glossy magazine.

Then, abruptly, everything changes: a man has a heart attack, and can't be resuscitated; the train is stopped, an ambulance called.

For at least three passengers on the 07:44 on that particular morning, life will never be the same again.

Lou witnesses the man's final moments. Anna and Lou share a cab when they realise the train is going nowhere fast. Anna is Karen's best friend.

And Karen? Karen's husband is the man who dies.

Telling the story of the week following that fateful train journey, One Moment, One Morning is a stunning novel about love and loss, about family and – above all – friendship. A stark reminder that, sometimes, one moment is all it takes, it also reminds us that somehow, and despite everything, life can and does go on.