After the great thunderstorm at the turn of the century, Henry comes home from school one day and finds a baby, peculiarly swaddled, and left among the hollyhocks. Aunt Agatha wants to call the police, but just then two antennae unfurl from the child's eyebrows, and a curious bleeping noise can be heard. Stranger still, a succession of unearthly visitors start calling at the house. Henry and Mr Perkins decide they need the help of Harvey Angell - the electrician with a touch of magic about them.