Penelope Keith at Her Majesty's Service

In celebration of The Queen's 90th birthday, Penelope Keith travels to the four corners of the Union to venture behind the scenes of Her Majesty's official royal residences. Penelope continues her journey at the Queen's official Scottish residence, the Palace of Holyroodhouse, where she discovers a unique 1000-piece royal silverware service and steps into the ill-fated bed chamber of Mary Queen of Scots. Penelope also boards Her Majesty's floating royal residence, the Queen's beloved yacht Britannia and peeks into the Queen's private quarters. On the west coast of Scotland, Penelope visits Inveraray Castle and the Master of the Royal Household of Scotland. Penelope takes aim with some archers and meets the the Royal Falconer at Borthwick Castle in Midlothian.

This time Penelope is in Northern Ireland, visiting the Queen's official Royal residence, Hillsborough Castle. Penelope meets the household staff responsible for raising the flag, buffing the brass and turning down the beds for Her Majesty's visits. She also gets an exclusive look at a long lost scrap-book of hand-written royal menus and invitations, dating back to 1925, shedding light on the tastes of the day. Penelope meets the Queen's bugler. She uncovers an unexpected treasure from the Queen's 1953 coronation tour and finds out how The Queen's simple act of crossing a road in Enniskillen in 2012 helped unify two fractured communities.

On the final leg of her journey, Penelope visits Wales, where she explores regal links - from ceremonial investitures to Pembrokeshire corgis and the Royal harpist. She starts her journey at Caernarfon Castle, where Prince Charles was invested as Prince of Wales in 1969. Penelope is serenaded by the male voice choirs of Anglesey and Bangor, and visits the Royal Mint. She meets champion Welsh dog breeders; and in the valleys of south-west Wales, Penelope visits Aberfan, the scene of a disastrous coal mining accident in 1966.