Much-loved Calleshire research chemist Derek Tridgell has been ill for some time. On his deathbed, his incessant but unintelligible mutterings culminate in a cry of murder.
Detective Inspector Sloan and Detective Constable Crosby are brought in to investigate whether these are just the ramblings of a man at death's door or a real confession at the final hour.
Their enquiries uncover three tragic deaths that may be linked to the deceased's last words: an accidental drowning at a rival chemist manufacturer, an old friend of Derek's killed in a caving expedition and his son walking away unscathed from a fatal car accident.
It’s a complex case for Sloan and Crosby.