EP1
A wealthy couple in their sixties are found dead by their daughter on Easter Sunday 2023 on the island of Mersea, Essex.  Carol and Stephen Baxter died in their armchairs with no sign of a struggle and police rule out carbon monoxide poisoning.  Senior Investigating Officer Lydia George and her team discover a mysterious will that leaves everything to the Baxters’ daughter Ellena and their family friend Luke D’Wit.  The detectives find out that Luke D’Wit was helping Carol Baxter as a carer as her health slowly deteriorated. Carol was closely following the advice of a mysterious American doctor promising to cure her thyroid condition.  A postmortem reveals that the couple had lethal levels of antihistamine and fentanyl in their systems.  Ellena and Luke are arrested on suspicion of murder as detectives search for answers.

EP2
Detectives raid Luke D’Wit’s home and seize a huge stash of prescription drugs, including fentanyl and antihistamine, both found in the Baxters’ postmortem. Police press Luke to explain his relationship to Carol Baxter’s mysterious American physician, Dr Andrea Bowden. Luke has been mixing ‘medicinal’ drinks for Carol on Dr Bowden’s instructions, yet detectives can find no trace of her existence.  Ellena Baxter is completely cleared of her parents’ murders and agrees to be interviewed as a witness for the police.  She slowly realises that Luke has been a cuckoo in the family nest. After detectives spend months combing Luke D’Wit’s multiple digital devices they piece together the scale of his deception and cruelty.