River Cartwright is a mess. Or that’s what people keep telling him, anyway.

Following last season’s reunion-spoiling revelations about his father (ex-CIA operative Frank Harkness) and his father’s past (raising children to be super-soldiers), the galloping young stallion (played by Jack Lowden) hasn’t been able to screw his head on straight. Lamb (Gary Oldman) unfavorably compares him to a “crack-up, a drunk, [and] a psychopath.” Standish (Saskia Reeves) reprimands River for not dealing with his issues as well as he could (a.k.a. her version of Lamb’s blistering reproach). And Louisa (Rosalind Eleazar) lays it out as plainly as can be: “You’re a mess,” she says. “You’re not allowing yourself to feel things that you should be feeling.”

Hawaiian war leaders spread their capes out in a show of defiance while a line of spearmen stand behind them in 'Chief of War' Jessica Chastain in 'The Savant,' shown sitting in an office chair, casually holding a cell phone, wearing gray sweats and black glasses

But River doesn’t see it, and frankly, neither do we. Sure, he snaps at Shirley (Aimee-Ffion Edwards) for no good reason, and yeah, his instincts aren’t as attuned as one would hope. (He makes an obviously errant pass at the worst possible moment.) But River has always been rough around the edges. His blunt bullheadedness is part of what landed him in Slough House, MI5’s storage locker for damaged agents, but it’s also what’s helped the haphazard team save the day, time and again, season after season.

So what’s the truth? Is River in desperate need of some R&R, or is everyone else projecting their own predicaments onto him? Well, after five seasons of Will Smith’s savvy Apple series, there’s little question as to who’s right in this regard: It’s Lamb. Our foul, flatulent father-figure may exaggerate a bit when belittling his enemies (and friends, for that matter), but cloaked under his aura of filth — like an adult Pig-Pen’s toxic dust cloud — rests a core truth. So as soon as Lamb backs a team he’s wont to disagree with, any mystery around River’s mental health status is settled: He’s a mess.

Even with one false impression exposed, splits in perception become a running theme of Season 5. When Roddy (Christopher Chung) almost gets hit by a van, Shirley claims she saved him from an intentional attack. But Roddy argues she was just “looking for an excuse to sexually harass me” and demands reimbursement for his damaged clothes. Is someone trying to kill him, or is Shirley’s personal loss (Marcus, last season) making her paranoid? Later, Roddy needs to look his best for a date with a woman way out of his league, yet his inflexible ego — and a cozy night at the club — make their shared passions seem weirdly plausible. Did Roddy, of all people, find love, or is she… being paid for her services (as his peers repeatedly contend)?

Distinguishing the appearance of truth from truth itself isn’t limited to individuals, either. Season 5 is set in a country gone “fucking mad.” When a campaign volunteer for the mayor gets killed by a gunman who supports the opposition, investigators prepare for the ramifications of a political attack. But when it turns out the shooter — who police initially believed had taken his own life — was, in fact, shot by someone else, the assumed situation spawns question after question: Who? When? Why?

Jack Lowden and Tom Brooke in 'Slow Horses' Season 5, shown holding up an ID and holding a knife between his knuckles, respectively Jack Lowden and Tom Brooke in ‘Slow Horses‘Courtesy of Apple TV+

As more strange situations sweep London, our favorite scruffy spies must decide what, who, and how much to believe. Is this a particularly bad week, filled with normal crises at an abnormal pace, or is there some sort of grand conspiracy connecting each bizarre emergency? Who among them should they listen to (besides Lamb), and whose vision is being clouded by personal bias? But also, how much is too much? If one far-fetched theory is proven credible, what other previously disregarded ideas merit reconsideration?

Invigorating in its temerity, Smith’s six-episode Season 5 is told with propulsive clarity (save for the mysteries you’re intended to guess at). Chaos is sorted into appreciable story arcs without diluting its overwhelming effect on our heroes. The element of chance isn’t treated as a convenient plot device, nor is it pushed aside entirely so a grand plan can click into place. Best of all, Slough House’s ability to make sense of the senseless becomes their key to saving the day. We may not always be able to separate reality from perception — sometimes differing perceptions simply can’t coexist — but we can still respect and value actual intelligence, especially when it’s used to solve public problems.

Problems “Slow Horses” directly links to anti-intellectualists, ignorant bullies, and willful distorters of the historical record — natural enemies of any self-respecting spy. They don’t call them intelligence agents for nothing, and Season 5 is a nice reminder of their basic function: not only to know more than your Average Joe, but to apply that knowledge toward keeping the peace.

River, very much looking the part of an internet boyfriend on the rise, is a mess, and Lamb, the living embodiment of “don’t judge a book by his cover,” makes for the perfect person to call him out. If we can all agree the clean-cut, handsome kid is more mixed-up than the slovenly old man about to clear the room with his farts, then maybe there’s hope yet for a shared reality rooted in truth. Fingers crossed.

Grade: A-

“Slow Horses” Season 5 premieres Wednesday, September 24 on Apple TV+. New episodes will be released weekly through the finale on October 29. The series has been renewed through Season 7.