When six childhood friends get together for their annual girl's weekend at the beach in Port Aransas, none could have believed it would be for the very last time. Nina Evans had been saddled with organizing the weekend each year, pulling five of her oldest friends together for a few nights of fun and reminiscing, the one time a year they saw each other. Each year was much the same—laughter, dancing, and lots of drinking. This time was no different. That is, until Jones walked out of the dance club with a stranger.

Jemima Pardon, a paramedic with a daft name and chronic asthma, has never had much in the way of good luck. The only things she attracts are traumatic jobs, and no one wants to work with her for long. But when Jem bumps into devil-may-care police officer Rosie Jones, her fortunes seem to be changing. Rosie is bright and funny, and she doesn’t mind that Jem can’t go far without her inhaler.

Detective Sanne Jensen (not blonde, not tall, definitely not Scandinavian) and Dr. Meg Fielding (scruffy, scatterbrained, prone to swearing at patients) are lifelong best friends, sharing the same deprived background and occasionally the same bed. When a violent kidnapping stuns the Peak District village of Rowlee, both women become involved in the case.

After the death of her grandmother, reluctant heiress Madilyn Marak agrees to stay with her grandfather at the estate for the summer. There, she finds an old diary hidden in an antique desk in the attic—The Apple Diary—written by her great-grandmother Isabel. In there, she finds the love story of Isabel and Lorah, along with a photograph of the two young women from 1933. The diary, like the love affair, was short and brief, but rich and vivid enough for her to feel a true bond with the women despite the heartbreaking ending.

A car lies crashed below a Welsh mountain road. One of the young women inside it is dead, the other badly injured with no memory of who she is or what just happened. All she has is a bus pass showing her photograph and a name she doesn't recognize. As she struggles to recover from her injuries, a startling revelation shatters everything she thought she knew, forcing her into an uneasy alliance with Detective Bronwen Pryce. With danger closing in from all sides, the two women must work together to uncover the truth - even if it kills them.