The last living descendent of Dr Jekyll and Mr Hyde is Tom Jackman. From time to time his alter ego Hyde wakes. Tom's wife hires a private investigator to find out why Tom left his family life six months previous.

Katherine drugs her employer after Tom takes it upon himself to discover the facts about Mr Hyde's personal life. The separation between Tom and Hyde gets weaker after an incident at the zoo. More secrets about Tom are revealed, when he meets a person connected to his past.

The wall between Tom and Hyde gets thinner and thinner and trying to suppress Hyde starts to affect the environment. Tom learns about the motivation of the organisation hunting him and Peter's part in the whole game. The involvement of Tom's wife Claire makes things a bit more complicated.

Tom finds himself a captive at the hands of an organization that has been planning its moves for over a hundred years. Meanwhile, Tom's marriage to Claire, the birth of their twins under impossible circumstances, and the first emergence of Hyde are recounted.

The home of Dr Henry Jekyll, Edinburgh 1886. Robert Louis Stevenson presents his business card, armed with a manuscript. With the appearance of fiction but the substance of fact, the story lacks only an ending. Jekyll's dying because he can no longer control the changes and his last secret will die with him as he tosses a vital piece of paper into the fire.

In a basement of an old country house, Claire learns the disturbing truth about her husband... and herself. Meanwhile, Tom and Hyde resolve their differences and launch an attack on the institute to regain their family.