The Culloden is a five-star luxury hotel near the village of Holywood in Co Down.
A popular location for weddings, it also offers an ideal location for discrete meetings as there are several entrances, some of them not visible to the prying eyes of the media.
They gathered outside the front doors again from early this morning and waited, watched and listened as the leaders of Sinn Féin, the DUP, Alliance Party, SDLP and Ulster Unionists arrived for talks.
But the talking actually started much earlier.
A DUP delegation led by party leader Jeffrey Donaldson slipped into the hotel, probably using one of the most discreet entrances, shortly after midnight.
They were there for an unannounced and hastily arranged meeting with the British prime minister, Northern Secretary Chris Heaton-Harris and senior UK government officials.
The meeting went on until around 2.30am.
"There was a lot of activity, a lot of talking and a lot of coffee," said one person familiar with the discussions.
The party's scheduled, publicised meeting later this morning also lasted much longer than any of the others.
The leaderships of Sinn Féin, the Alliance Party, SDLP and Ulster Unionists each had about 15 minutes with Mr Sunak and his team.
The DUP engagement last more than an-hour-and-a-half.
After an initial face-to-face meeting with Mr Sunak, the party's delegation and the UK officials worked in separate rooms, exchanging messages, before a further meeting with the British prime minister.
That suggests the party may have been provided with more details than the others as it's the DUP that Rishi Sunak needs to persuade that any forthcoming deal is good enough for it to return to powersharing.
Speaking afterwards, Jeffrey Donaldson said his party does not have a seat at the table and is not involved in the negotiations between the UK and the EU, but added that it is seeking to ensure the British government is aware of its concerns.
The party will hope those concerns are reflected in a series of engagements between the UK and EU over the weekend.
