Rose Arbustus is not like any other girl, in fact the Arbustus family is not like any family you are likely to have encountered.

Rose lives with her mother, Willow, and her grandmother, Sophora, surrounded by the botanical and scientific tools of their trade. Their greenhouse is full of unusual and exotic plants, one of which is Rose's best friend Dracula simia - or Simmy for short.

Their quiet and industrious lives are interrupted by a visit from a dark-robed and dangerous visitor. The fact that this man is Rose's uncle does not diminish the evil that surrounds him.

After Rose becomes seriously ill, and all the family's plants - not to mention the surrounding countryside - become infected with the scarlet spotted disease, Willow and Sophora realise that they must act fast to counter this deadly virus.

There follows a dangerous escapade around Edinburgh and London in search of the Environment Killer, who seems hellbent on destroying not just their family, but the whole of the natural world.

Rose, Simmy, Willow and Sophora will need to use all their botanical knowledge and skill, and draw on all their reserves of energy and bravery if they are to apprehend him and curtail his evil plans...