Beatlemania never really went away: it just found new objects of its affections, some in Asia. Prominent among those has been Japanese “idol” outfit Arashi, which since starting out two decades ago has sold more than 54 million copies of albums, singles and videos, and counting; 53 number-one singles (a Japanese record); 20 number-one DVDs, 18 of those consecutive; live audiences of more than 14 million people; industry awards galore and almost as many costume changes. Arashi stopped being a “boy band” and became an “idol group” some time ago. Its five members are in their mid to late 30s but have remained well scrubbed, polite and, offstage, unobtrusive: saccharine to some, son-in-law material to others. Arashi means “storm” and the group has, after a slow start, continued to kick up exactly that. So imagine the horror of 80 per cent of the collective when one of them decided that, after two decades, he wanted time out. “Shock waves over Japan” was among the headlines – in a country that has suffered nuclear devastation. The announcement and its aftermath comprise the nub of the oddly affecting, surprisingly poignant Netflix documentary series Arashi’s Diary: Voyage , which follows what may be the farewell tour of a pop-culture juggernaut, because no one knows if, from December 31 this year, it will be break or break-up for the famous five. Satoshi Ohno, approaching 40 and “the eldest, technically the leader” of the group, decided in 2017 that he had a “desire for freedom” beyond its confines. “Ohno breaks up the band” is an observation this column finds impossible to resist, and regardless of whether that turns out to be true, the traumatic news was still reverberating a few months ago when Covid-19 descended. By then, Arashi were deep into their gargantuan, technically dazzling 20th-anniversary concert tour, so if the statement was made for maximum impact the timing was puzzling. But such cynicism isn’t a quality that attaches itself to these genuinely pleasant chaps, whose characters are emerging fully now that the long-running series has reached the point at which each enjoys a dedicated episode. The latest arrives at the end of the month. The candid, access-all-areas presentation has brought out the hard work and sacrifice essential to a platinum-plated entertainment career, so whatever comes next one wishes all five of them well. Trackers takes on international crime syndicates and the illegal wildlife trade Marilyn Monroe may have been right all along. Diamonds could indeed be a girl’s best friend, not least if she’s mixed up in the Asian-funded illegal wildlife trade, Islamic terrorism and murder in the South African badlands – and has to disappear with all due haste. Flea (Trix Vivier) is the girl in question and the gems – blood diamonds – are central to a smuggling operation that’s part of a bigger picture involving international crime syndicates, al-Qaeda, state security, a plan to blow up Cape Town Stadium … and two black rhinoceroses. Caught in the middle of the escalating nastiness, meanwhile, is reluctant hero Lemmer (James Gracie), a rugged loner and fallen operative who’s determined to do the right thing, even if that means taking a few violent diversions along the way. Welcome to the precarious, hair-trigger world of Trackers (Saturdays at 10am on HBO Go and Cinemax; re-runs on the latter at 10pm), where the good, the bad and the decidedly ugly come together in a concoction of spy-agency intrigue, ruthlessness, derring-do, a dash of romance – even a mesmerising, kaleidoscopic Bosch-inspired title sequence. And if that lot doesn’t do it for you, there’s always the geologically sensational cultural cauldron of Cape Town to gaze upon.