now in the twilight of his career, Picard is relegated to space duty in the Solar System. He's been pressured to retire, but refuses.
nevertheless, he gets the chance to save Starfleet and the Federation one more time, as a shadowy cabal shows up, composed of space billionaires, militant reactionary elements of Starfleet, and proponents of a regressive, close-minded, hypocritical space religion (in the show they'll call it Fundamentalist Christianity, but claim it has no relation to 20th-21st century American Christianity (quote: "no, this Christianity was founded by
another guy named Jesus Christ, who lived in 22nd century Israel.") Also, they're funded by the Romulans seeking to destabilize The Federation. and their figurehead is a pudgy, lying, sleazy space developer named Donald Mudd (a descendent of 1960's Star Trek scammer
Harry Mudd)
Okay, so the cabal is seeking to overthrow the socialist space faring utopia of The Federation, and replace it with a capitlist system with the means of production all solely under their control. And under them, Starfleet will end their primary mission of peaceful exploration, and immediately expel all Klingons serving in its ranks, and use that as a ruse to goad the Klingons into all out war, serving to unite all the Federation in their capitalist plan.
They launch a coup attempt on Earth, and the only Federation ship around available to stop them is the ship under Picard (not the Enterprise, which is a frontline ship, but a shitty obsolete Starship, helmed by a skeleton crew).
through a careful use of diplomacy, politics, technical wizardry, sleight of hand, and a couple photon torpedoes, Picard foils their plan, and a grateful Federation puts him back in charge of the Enterprise.