Downton is almost entirely powered by longing, but acting on it is always risky. This is one of many lessons aristocratic arriviste Tom Branson, who at the moment might as well just be a potato in a top hat, needed to learn - and he learned it this week as reptilian lady's maid Edna confirmed that her generously proferred tumbler of (spiked?) whiskey had indeed done the trick: after last week's party, Branson had dipped his pen in the company ink.
A fraught, snatched convo in the corridor saw Edna ask for acknowledgement and Branson try to quell the crisis, bleating that he'd made "a mistake". Indeed he had. Moments later Edna materialised in his room and drew herself up to her full 7ft 6in height, spinning her eyeballs furiously. Scaly spines ripped through the back of her uniform and green ooze stained the sideboard.
She menacingly asked Branson if he would marry her should she be pregnant, and whether he regretted his brief return to downstairs service. "There is nothing but regret in me," he said, terrified at the thought not only of losing his social standing, but more urgently of having fathered the very child of Satan.
There was only one thing for it: a trip to Mrs Hughes' command bunker. While Edna was in the boot room, buffing suede with her tongue and gloating to lesser evil Thomas, who'd witnessed her initial debate with Branson, that "There'll come a day when you'll be glad you kept in with me," Hughesy got to work.
In series one and two, Agent Hughes preferred to bring down the enemy via eavesdropping, using her intimate knowledge of the Downton air vent system if necessary. But now she was fighting hard and dirty, inviting Edna to her headquarters and then slapping her, almost literally, with the birth control manual she'd found in Edna's room. Sadly we weren't shown Mrs Hughes, in a black catsuit, scaling the wall of the Abbey before gaining entry through Edna's window using a glass cutter and some improvised explosives.
But what we did see was exciting enough: Mrs H, eyes ablaze, calling the pregnancy bluff and threatening Edna with some sort of horrific Geneva-convention-busting enforced medical examination: "I'll lock you in this room and tear the clothes from your body." Did Edna feel lucky? No. Next morning off she went, scuttling sideways across the lawns, apparently never to be seen again.
Mrs Hughes had various other schemes on the go. Her marriage to Carson will surely be the emotional peak of series twelve - she's playing the long game, which sometimes means making a counter-intuitive move. This week it was giving Carson a framed photo of his lost love Alice as a gift. The frame suggests closure, while the memory of the kindness of Mrs Hughes's gesture will now be mixed in with any romantic stirrings Carson may have upon looking at the picture. Also, it's a reminder that Alice was a heavy-browed, stern-looking sort. A touch of the Russian army corporals. Hughes is not daft.
One situation Hughes cannot fix is the marriage of Anna and Bates. Edna's departure gave Anna the opportunity to further distance herself from her blameless, ignorant husband by suggesting that the extra work now required should mean she moves out of the marital cottage and back to Downton. Joanne Froggatt, who has the unenviable task of essentially performing her own separate, vastly more serious drama, was brilliant again, especially in the crushing moment when it was announced that Lord Gillingham was to return - bringing the possibility of his valet and Anna's rapist, Green, also coming back.
In a rare error of judgement, Hughes encouraged Anna to take a break from her suffering. "There can be no break from it," came Anna's bleak reply.
Gillingham was at Downton to ask Mary to marry him, which proved to be the end of their whirlwind non-romance. He'd popped up first when Mary, Branson and Rose appeared at Aunt Ros's house in London, as part of a double-date set-up completed by Sir John Bullock the plot-enabling makeweight.
At a jumping jazz club, three things went wrong. Mary was backed into a corner by Gillingham and told him that, although she was more or less hot for him - Downton was like school, she said: "You've made me play truant and I like it" - she really wanted to spend more time planning how to farm goats more profitably, and sorting out the drainage in the lower field.
Meanwhile, colossal lush Sir John was leading Rose in a potentially neck-breaking sloshed quickstep, interrupted only when he had to dash out of the room to vomit. It looked like he might not even have time to find a peasant to be sick onto - hopefully a stout member of the club's staff stepped up. This left Rose adrift on the dancefloor. She was rescued by Jack Ross, the club's singer, who'd had a lot of close-ups and had sung two different songs, alerting us to the prospect of him getting some dialogue as well.