Titus is a young corgi puppy, growing up in Windsor Castle. There is lots he must learn - how to sit upright and beg for a custard cream biscuit, how to ask nicely to go outside, and how not to trip up Prince Philip. Soon he becomes a favourite of the Queen. She even breaks a lifetime rule - and lets him sleep on her bed at night! And it is because of Titus that Her Majesty finally does something very surprising...