It began with a short but worrying statement. Less than 48 hours after a frail but smiling Queen Elizabeth II was photographed appointing new Prime Minister Liz Truss, her doctors said they were "concerned".
An unprecedented medical bulletin issued by Buckingham Palace said the 96-year-old queen was under "medical supervision" but "remained comfortable" at her Scottish retreat, Balmoral Castle.
The announcement at 12:32 pm (1132 GMT) sent shockwaves through parliament, where MPs had gathered to hear Truss announce a two-year freeze on energy bills.
Within minutes, the office of heir to the throne Prince Charles had announced that he and his wife Camilla, who were already staying on the Balmoral estate, had arrived at Balmoral Castle.
It is believed the queen's daughter, Princess Anne, also made it to Balmoral in time as she too was in Scotland.
Both are thought to have been by the queen's side when she died on Thursday afternoon.
Other members of the family, however, faced a long and ultimately unsuccessful dash from London.
The second in line to the throne, Prince William; the queen's other two sons, Princes Andrew and Edward; and Edwards' wife Sophie, who was particularly close to the monarch; arrived in a cold, grey Aberdeen aboard a special RAF plane late in the afternoon.
William, who has now become the heir, then took the wheel of the car for the 80-kilometre (50-mile) drive to Balmoral.
But by the time the grim-faced royals swept through the gate of Balmoral just after 5:00 pm, it was already too late.
Around half an hour earlier, at 4:30 pm, the prime minister had been informed the queen had died that afternoon.
Prince Harry, Charles' second son, meanwhile was still en route from London.
Initial announcements by the couple's spokesperson said both he and his wife Meghan would travel to Balmoral.
In the end Harry made the journey alone and was still in the air when the official palace announcement was made to the world at 6:30 pm.
He did not arrive at Balmoral until much later.
BBC royal correspondent Nicholas Witchell speculated live on air that Meghan -- who has made a string of damaging criticisms of the royal family -- did not make the journey in the end, for fear "she might not be terribly warmly welcomed".
The palace statement said the queen had died "peacefully" but in line with royal tradition did not give any cause of death.
Sources told the Daily Mail newspaper there had been "no chronic condition".
The queen had been undertaking far less work in recent months, but on Tuesday she nevertheless met both the outgoing Prime Minister Boris Johnson and the incoming Liz Truss.
The sources told the daily the queen had been in good spirits -- despite her recent and well-documented "mobility issues" -- but took a sudden turn for the worse duting the night of Wednesday to Thursday.