Last Night's TV: Justin Lee Collins: Turning Japanese, Channel 5<br/>Skins, E4<br/>Kidnap and Ransom, ITV1

There's a lot that's quite odd about Japan. Is it OK to say that? I mean, really. They do karaoke... sober. And they have kiwifruit KitKats. And coffee jelly (in Starbucks). And lots of other things that aren't quite normal, like manga and robots.

Anyway, Justin Lee Collins is here to show us a few more, in Justin Lee Collins: Turning Japanese. It's not quite clear why he's been appointed as guide – "I don't like manga or robots," he clarified early on, "and I've never been this far from home" – but it doesn't really matter. He's charming enough and Japan's odd enough for the two to work just fine.

Even more charming was Justin's guide, Mai. One of the first places she took him was an ice-cream parlour, complete with all those horrible flavours the country is famous for: snake and eel and jellyfish. As it turned out, Japanese people don't actually like these things (in their dessert). The idea is sport. Groups of teenagers sit around playing games, the forfeits taking the form of frozen yukiness. "It's funny and fun," explained Mai, patiently. "Like a drinking game," said Justin. Put like that, it doesn't seem so weird after all.

Not that things were entirely normal. Japan, we learned, is in the grip of a population crisis. Birth rates are plummeting, and no one's getting married. The problem, explained Mai, is a growing mismatch between the country's men and women. The latter, evermore empowered and assertive, are struggling to find satisfactory partners in the pool of increasingly effeminate men, a pool that regularly wear bras to "reduce stress", and can buy thongs in rainbow colours. It's "carnivores," she said, versus "herbivores." The result is a booming market for dating classes: rooms full of lovelorn young men earnestly doing facial exercises deemed crucial to romance. Justin attended one, of course, and came out with high praise. "You should all follow his example," said the teacher. "To help [and here the subtitles inserted a pair of quotation marks] 'spice' up your love life." As well as boosting amorous education, the lovelorn state of the Japanese man has fuelled an enormous sex-doll industry – the biggest in the world. One chap had a whole room of them; he even wears a wedding ring to signify his commitment. This is properly weird, though not, I suspect, all that typical.

Of course, while the men are all off attending classes and sobbing into their sex dolls, the women need something to keep them entertained. And so the rise of the male escort: whole districts of cities given over to bars where women can go, select a "date" for the night and spend the evening flirting, chatting and spending money (though not, it seems, much more than that.) Justin, most likely speaking on behalf of all British men everywhere, was perplexed. "There's a really pretty girl over there. It's her birthday. And she's here. Why?"

Almost as mystifying as the Japanese – the world of teenagers. After a disappointing series last season, Skins is back, its popularity unlikely to have been dealt many blows by the controversy currently unfolding over America's adaptation (So much sex! And drugs! And hormones!). As per tradition, the entire cast has been overhauled, replaced by a fresh crop of pubescent, Impulse-spraying tearaways. The soundtrack has had a similar update. Last night, The Vaccines and The Strange Boys both made an appearance.

The programme's success has been based, largely, on its ability to accurately reflect teenagers' lives, as well as the lives they aspire to, the drugs they want to be taking, the parties they want to be going to. Last night looked likely to continue the tradition. The episode centred on the arrival of Franky Fitzgerald at sixth form. Crop haired, androgynous, with a fondness for oversized suits, she attracts bullies like paperclips to a magnet. An unfortunate incident at the bus stop saw her arrive at college aboard an old person's mobility scooter. Crashing the (stolen) thing into the bike rack didn't offer much hope of a low-key entrance. Of course, Franky isn't really the hopeless case she appears. After a quick shopping centre makeover, she emerged butterfly-like with a bit of eyeshadow, thereby commencing a war of jealously and one-upmanship with resident totty Mini. Along the way there were drugs, skinny dipping, parties and shoplifting. Just your average week as school child, then.

The final episode of Kidnap and Ransom posed as many questions as it answered. Naomi Shaffer's daughter was returned (minus, in a rather bleak twist, one finger). We know why she was taken now. Shaffer, during her time as a hostage in South Africa, had promised her kidnappers a piece of her husband's work. Worth billions, his formula for an anti-obesity drug could be traded on the black market. And we learned that Dominic King didn't, in fact, shoot the kidnappers on his last rescue mission when they returned his rescuee dead.

What never became clear was the source of King's brooding, troubled interior. What was it that happened to him in Iraq? What is it that Alexander keeps referencing? Instead, hostage recovered, he simply transformed: returning home in time for dinner with the wife. And what of the Shaffers? Alex may have what he wants, but are they really safe? ITV could do worse than bring back a second series of this. It's so much better than everything else it does.