It is Bonfire Night in Britain, the 400-year-old story of gunpowder, treason and plot to blow up Parliament. Before the fireworks and the ritual burning in effigy of Guy Fawkes on bonfires, Chelsea FC play Manchester United at Stamford Bridge.
A mere game? No match for the attempt of the 5th of November 1605 by Catholics to destroy the Protestant state in England?
Think again. This is no ordinary contest, 11 versus 11 and all that. It is the collision between two clubs, the London one owned lock, stock and barrel by Russia's Roman Abramovich against Man United, owned principally by the Glazer brothers and quoted on the New York Stock Exchange.
Blue against red. Chelski against United. Jose Mourinho, back and brooding at Stamford Bridge where Abramovich twice hired and twice fired him. Antonio Conte, the Italian coach who turned Mourinho's failed team into champions six months ago, but who is now feeling the heat of temporary failure in the House of Abramovich.
We all know where that ends, and if Conte, who recently moved his wife and daughter to London, felt he had earned at least one more full season, facing Mou in the opposite dugout will swiftly disabuse him.
Managers and coaches do not win football games. Players do. And any rational preview of tonight's encounter in West London might highlight Nemanja Matic trying to destroy Cesc Fabregas.
Last May, they were shoulder to shoulder in Chelsea's midfield, Matic the physical presence, Fabregas the pass master, releasing the ball for Eden Hazard the wizard or Diego Costa, the beast who would kick his own granny for a goal.
For whatever reason, those players collectively won the League under Jose in 2015, then downed tools and refused his orders during the next, imploding season.
The nub of the fallout was Mourinho's ego. His boast that the players were not as good as he made them appear to be, backfired.
Jose Mourinho, back and brooding at Stamford Bridge where Abramovich twice hired and twice fired him. Antonio Conte, the Italian coach who turned Mourinho's failed team into champions six months ago, but who is now feeling the heat of temporary failure in the House of Abramovich. Rob Hughes
And when Mourinho returned in charge of United a year ago, his former Chelsea players gave his new team a 4-0 hiding. Mourinho declined to congratulate his successor Conte.
Instead, he whispered in the Italian's ear that it was disrespectful of Conte to run like a child on the touchline, celebrating goal after goal. "At one-nil, you can celebrate," Mourinho implied, "at four-nil, you don't celebrate. You don't humiliate."
The performance was the humiliation. Conte did as Conte always does, celebrating as if he is still a player.
Lately, though, the pendulum has swung. United, big and powerful in the mode of Matic and with half the side rebuilt under Mourinho, hammer lesser opponents into submission. Man United are Devils all right - against the lower half of the Premier League.
The game of attrition is reflected in the fact that of 47 goals scored in the final 10 minutes of league games this season, United have 10. In effect, they play Mourinho football, grinding the opponents until they wilt, punishing them when they are weary.
Mourinho, not in the best of moods while he is hounded by Spanish authorities seeking €3.3 million (S$5.2 million) of unpaid taxes during his time coaching Real Madrid, is also at odds with United fans he feels do not appreciate his tactics. The Manchester United Supporters Trust offered to "engage" the manager on issues of style and Mourinho's complaints. "I cannot meet a quarter of the planet," Mourinho responded through the media. "A quarter of the planet is Manchester United Red."
He is seething, again. Conte is feeling the pressure of an inconsistent start, and the shock of Chelsea's 0-3 loss in Rome in the Champions League on Wednesday.
"I try to transfer my suffering to my players," said Conte. "It's right to suffer after we lose."
He will suffer tonight. From Mourinho, from his inner camp, and from the big boss at the Bridge.
Abramovich usually leaves Marina Granovskaia, his special adviser from Moscow, and Michael Emenalo, the Nigerian-born technical director, to pass on the messages of satisfaction or otherwise to the coach and team.
Visits by the oligarch himself to the Chelsea training base at Cobham, south of London, are rare and meaningful. He goes there to uncork the champagne when the great prizes are brought home, and goes there to personally convey displeasure when standards drop.
Conte was less than wise to communicate through the press that he felt let down during the summer transfer market.
Costa was cast out, and eventually sold. Romelu Lukaku, the presumed replacement target, chose instead to join United. Alvaro Morata then arrived from Spain. And while Lukaku would have been a like-for-like swop for Costa, Morata has more movement, but less physical might.
Add to that the hamstring injuries that have deprived Chelsea of Victor Moses at right wing-back and the terrier N'Golo Kante in midfield, and it's clear Chelsea are not the force they were last season.
The fact the Blues are in the Champions League this season and had a clear run at the EPL title last time, is closely correlated to those injuries. But Mourinho hears the "suffering" from West London and scoffs, this time justifiably.
"Probably I should cry every week about our injuries," the United manager said. "I know I moan about a lot of things, but I don't speak once about Pogba, about Rojo, about Fellaini."
That much is true. He tends not to speak about, or to, players who are sidelined. If they are out, they are of no use to him.
That cold human relationship was felt, for example, by Hazard. The star of Chelsea on a good day, irrelevant when his form or fitness dipped, the Belgian felt the sting after Mourinho left. The next time they met, on opposite sides, the manager hatched a plot to immobilise Hazard. He attached Ander Herrera to him, with licence to kick the Chelsea man into submission.
It's a plan, but not for the faint-hearted or the football lover.