A woman convicted of poisoning a child undergoes the latest lie tests in an attempt to clear her name. Susan Hamilton was sentenced to four years in prison for poisoning the little girl, who cannot be identified for legal reasons. She has always protested her innocence and hopes to appeal against her conviction. The child had been diagnosed with a terminal metabolic condition. To help her grow and develop she had been fitted with a feeding tube and Susan managed her feeding regime. However, the child was admitted to hospital with massive blood sodium levels, and suspicion fell upon Susan. Had she added salt to the little girl's feeding tube? The police testified that a syringe full of salt was found in Susan's kitchen. Susan denies any knowledge of it. Will the lie detector help Susan to clear her name, or finally prove her guilt?