Speeding round the race track in Geneva, ageing playboy Alan (Ben Lawrence) gets annoyed when his bouffant blonde wife Jessie circles above in a helicopter, cheering him on. Quite why his wife's encouragement so vexes Alan is one of many mysteries posed in Diamond Connection before writer-director Sergio Bergonzelli decides he could not be arsed to provide any answers. So brace yourself. Away from the racing circuit Alan happens to be shagging sultry Magda, with Jessie's approval. Magda's father happens to be a man named Ferguson smuggling a cache of stolen diamonds on a plane that is struck by lightning. Days after the plane crashes into the murky sea, Ferguson wakes up in a Turkish hospital with no diamonds, no memory and his face in bandages. On the plus side he is in the care of a particularly glamorous doctor played by babelicious Barbara Bouchet. Hey, things are looking up.
However, enigmatic Dr. Karen makes a phone call to Alan and his conspirators who worry that Ferguson has lost their loot somewhere in the Bosphorous. On Jessie's orders, Alan takes Magda to visit her dad in the hope of reviving his memory. But the pair are intercepted by stone-faced tough guy Fred (Gordon Mitchell), another ambiguous individual after the jewels for his own enigmatic ends. Fortunately, Alan is rescued by more of his fellow conspirators including his old pal Sam a.k.a. the Professor, finger-snapping disco buffoon Mark, the latter's giggling idiot girlfriend Janey (who later laughs herself silly on discovering a dead body: "It's funny how no-one ever knows anything about corpses") and even Alan's toy pistol wielding little son. The kid looks all of eight years old yet cheerfully punches Fred in the gut and seems to be in on the whole diamond smuggling plot. Maybe the family that smuggles together, stays together? Unlikely given throughout the whole thing Alan barely acknowledges his son. Anyway, a Swiss Police Inspector (William Berger) takes an interest after Ferguson (whom Alan none-too-kindly nicknames 'the Mummy') is ambushed by yet another man in bandages. Now surprisingly agile, Ferguson slits his assailant's throat then sneaks out of hospital to meet another mysterious young woman with whom he spies on Alan and co. while they search the sea for the missing diamonds. Meanwhile, Dr. Karen wafts around the peripheries of the plot, seemingly more in the know than anyone else especially viewers. Seriously, what the heck is going on?
Make no mistake, Diamond Connection does not make one lick of sense though for bad movie fans provides a fair few trashy laughs. At first some impressive locations suggest the film had a healthy budget until we cop an eyeful of a pathetic toy plane struck by cartoon lightning! It was a final flourish in Euro crime genre for several stalwarts including one-time sword and sandal star Gordon Mitchell (as the screen's unlikeliest Arab until Doug McClure in Cannonball Run II (1983)), spaghetti western veteran William Berger and not least giallo and sexploitation goddess Barbara Bouchet, still looking pretty dang hot advancing into middle age although more a special guest star. Sergio Bergonzelli tells an absurdly complicated story in the most incoherent way possible, more invested in gratuitous aerobics action with disco girls in lycra and leg-warmers than linear plotting. Best known for his daffy giallo In the Folds of the Flesh (1970) with down-on-her-luck star Pier Angeli, Bergonzelli dabbled in many genres much like any other Italian workhorse including spy films (M.M.M. 83 (1966)), spaghetti westerns (Colt in the Hand of the Devil (1967)), sexploitation (School of Erotic Enjoyment (1971), Our Lady of Lust (1972)) and historical adventures (The Sea Pirate (1966)). He went on to make Blood Delirium (1988), a particularly deranged horror outing pairing Gordon Mitchell and John Philip Law. His films tend to be a little nutty.
Choppy editing and mismatched footage sit uneasily with the odd stylish shot or bravura action sequence. Around this time critics carped that Euro icons Alain Delon and Jean-Paul Belmondo were getting too long in the tooth to convince as tough guys. But those stars were still lean, mean, buff-looking guys performing their own stunts well into their fifties. By comparison ostensible lead Ben Lawrence (in his only film credit) and sidekick Sam resemble greying, paunchy, late middle aged playboys on holiday who decided to make a home movie so they could play at being action heroes. Viewers not wincing at the sight of Alan in a shorty judo robe or thong (yecch!) will either bemoan the absence of a single compelling or likeable character or else wet themselves when Alan casually dumps two dead friends into the sea ("Those two can hold hands and giggle forever") or Berger's Inspector reveals his game plan is to sit back and let everyone kill each other (see also Voodoo Black Exorcist (1973) and The Killer Must Kill Again (1975) for further examples of apathetic policemen in Euro cult cinema) and the sheer number of times Barbara Bouchet says "I am a doctor, after all."
Bergonzelli eventually resolves his nonsensical plot via a round of ridiculous punch-ups, cat fights and contrived twists set to a pounding disco beat. Yet the final reveal proves weirdly satisfying bringing new meaning to the old adage one person's terrorist is another person's freedom fighter. Worth watching if you always wanted to see a gun-toting Barbara Bouchet chase someone down in a speedboat.