Guy Hubble is alerted to a planned attempt to assassinate a member of the royal family. During his investigation, he finds himself in league with a charming hotel guest.

Hubble is assigned to accompany the Prince on a shopping trip to the jewellers. However, a mix-up leads to a hostage situation.

Hubble is sent on leave for seven days to avoid havoc at the Queen's Birthday celebrations. However, he comes face-to-face with an old enemy.

Hubble is enlisted to investigate a burglary at Buckingham Palace after several paintings are taken from the Queen's collection.

The security service fakes Hubble's death, in order to place him in an uncover investigation to seek out a mole who is leaking state secrets to the North Koreans.

Hubble is tasked to look after the Princess during a hen party held by her friend. However, he soon manages to lose sight of her.