It's mid-Winter in the Cornish seaside town of St Foy. In the midst of a family birthday party Emily Duggan, missing for three years and presumed dead after murdering her best friend Star Bright, arrives unannounced. To the bewilderment and shock of her family, Emily insists she didn't do it and has an alibi, but refuses to answer any questions.

Led by Belle Harrington, the Curiosity Club, including Emily's aunt Bette, start their own investigation to find the real culprit, as the police re-open the unsolved mystery of Star Bright's murder.

As the case progresses, old, uncomfortable secrets re-surface. Who was the real Star Bright? Could finding the truth about her past reveal her killer? If her killer wasn't Emily, could it have been one of the four students with whom Emily and Star shared accommodation at the eerie, now abandoned house on the Moor nicknamed 'Bedlam Heights.' Or was it another family member? Or someone from Star's bizarre past?

Belle and the Curiosity Club pose these and many more uncomfortable questions, as certain residents of the town become quietly but increasingly determined the case will never be solved.