Justin Thyme - 13 year-old inventor and billionaire
Robyn - his older sister
- their baby brother
Sir Willoughby - their father, Laird of Thyme
Lady Henny - their mother, celebrity explorer
Lyall Austin Thyme - their long-lost grandfather

Verity Kiss
- the nanny
Professor Gilbert - Justin’s private tutor
Mrs Kof - the cook
Angus Gilliechattan - the gardener
Morag Gilliechattan - the housekeeper
Knightly - the butler

- a postman
Hank and Polly - Lady Henny’s film crew
Sergeant Awbrite and PC Knox - the local police

- a computer-literate gorilla
Burbage - Mr Gilliechattan’s cockatoo
Tybalt - Mrs Gilliechattan’s cat
Fergus - Jock’s Scottie dog