In Stephen Mangan's own words, Dirk Gently is "charming, ­irritating, bright, funny, hapless, unreadable, transparent, roguish, chaotic, philanthropic and possibly dishonest".

That's a lot of character traits to be dealing with, but we discover yet another, equally surprising side of his personality tonight as he shares fish and chips with a new female friend.

Dirk and MacDuff (Darren Boyd) are at Dirk's old college at Cambridge to take up the post of head of security.

His former teacher, Professor Jericho (Bill Paterson), is trying to develop artificial ­intelligence and he's afraid that someone is attempting to steal his research.

However, Dirk's more concerned with breaking into the college records to find out why he was expelled as a student.

It's just a shame creator Douglas Adams isn't around to see how Howard Overman has ­transferred Dirk to the screen.

He'd definitely approve.

Dirk Gently is bedding in nicely. Where the show was groping around for a strong identity last week, this second story is much more involving. The series shares the same character dynamic as Sherlock - brilliant but antisocial hero, likeable Everyman-sidekick - but goes its own way with humour and eccentricity.

Dirk returns to the Cambridge college that expelled him for cheating, and finds a centre of research for artificial intelligence. Catching up with his former mentor, Professor Jericho (Bill Paterson), Dirk is soon plunged into a conspiracy of theft, murder, cutting-edge robotics and online gaming. It ends up being this week's oddest combination: fantastical and touching. It works wonderfully.

Dirk Gently episode 2 review

Episode 2 of Dirk Gently much improved, with plenty of energy, silly sci-fi, and fun...

Expelled from university 20 years ago, Gently returns to Cambridge "in triumph" to become a security consultant for his former mentor, Prof Jericho (Bill Paterson). The triumph is shortlived as the detective and sidekick are charged with guarding a valuable robot, which promptly goes missing. Worse, a death follows and the two men attract the attention of the law. Better than last week's opener, it adds a hint of darkness and an unlikely love story to the series staples of outrageous coincidence, Gently behaving appallingly and plain silliness.

The main plus point for Dirk Gently is having the consistently great Stephen Mangan on board in the lead role - he's certainly one of our most watchable comedy actors, and is in particularly fine form as the infuriatingly self-sure (but still rather lovely) private detective who believes in 'the fundamental interconnectedness of all things'.

Since the superb Sky One comedy Spy, my eyes have also been belatedly opened to the huge talent of Darren Boyd, who plays Gently's rather more conventional assistant-slash-business-partner MacDuff - so all in all I can't help but come to Dirk Gently with a whole heap of goodwill.

But I think my enjoyment of this episode can be put down to more than that. It's a great-looking thing, and the script was sharper than the pilot - I particularly enjoyed the line "his cheque bounced like the proverbial basketball... on a trampoline." Miss out the word "proverbial" there and it's prosaic; with it, it's a winner. There were little gems like this throughout the hour, and Douglas Adams's genius sense of the absurd is perfectly encapsulated in the idea of 'zen navigation': find a car that looks like it knows where it's going, and follow it. Pretty silly, but highly entertaining.

I struggled with Dirk Gently (Monday, BBC Four). It had nothing to do with Stephen Mangan's considerable comedic talents, still less with Darren Boyd who plays Macduff, the Dr Watson to Dirk's Holmes. It is more to do with my devotion to Douglas Adams, upon whose comic novel this series is based. Adams was never well served by TV or film adaptations of his work, even big budget ones such as the 2005 film of The Hitchhiker's Guide to the Galaxy. His books always worked much better as radio adaptations that could leave the listener's imagination to fill in the gaps (indeed the Radio 4 version of Hitchhiker's even managed to be better than the book).

Jeeves and Wooster was similarly hard to make work on screen. Though Fry and Laurie's version was as good as any TV adaptation could be, it tried to tell the story through dialogue alone, which merely drew attention to the silliness of the plots. In PG Wodehouse, as in Douglas Adams, 90 per cent of the pleasure is in the prose, the narration, the felicities of language.

Over the course of a novel, Adams could afford to be quite subtle about Dirk's big idea, that all things are fundamentally interconnected. A TV adaptation can't be, and, as it keeps labouring the point, you find yourself saying: "Yes, yes, I get it." Perhaps as the series develops they will tone down this side of things.

Finally, and this is an anoraky point, Mangan looks nothing like the Dirk of the novels. At Cambridge Dirk was "rounder than the average undergraduate and wore more hats", and in later life he becomes rounder still, and scruffier, and more chaotic. Mangan seems too neat, too thin, too orderly.

TV review: Dirk Gently

The more you think about it, the less sense Dirk Gently's chaos theory makes.

With regards to Dirk Gently, there's nothing wrong with the actors Stephen Mangan and Darren Boyd and some nice moments from Howard Overman's script. It's just that those qualities in the end spread a little too thinly over a nonsensical thriller plot.

It's supposed to be nonsensical, of course - Dirk's belief that "everything is interconnected" pretty much necessitating a chain of wildly improbable coincidences and consequences. But since anything can happen you don't very much care about anything that does, and Dirk's metaphysical musings about "Zen navigation" and the complexity of the world begin to get repetitious quite quickly. There were laughs, including a nice reveal when Mangan opened a Valentine's card in the middle of a complacent speech about his powers of attraction to find that the inscription inside read "I hate you, you're a pig". But they were far too widely spaced in a script that could have done with a lot more editing. Scorning someone's belief in astrology, Dirk asked him whether he really believed that planets "billions of light years" away could affect human destiny. Millions of miles would cover it, Dirk, and yes, you might justly point out that this scientific pedantry is irrelevant. But I probably wouldn't have noticed if he hadn't used the same phrase three times. Or if I'd been laughing enough to distract myself.

Review: A five-star script filmed on a one-star budget

Dirk Gently's sparkling script is let down by a threadbare budget, leaving what would have been a marvellous radio drama floundering on TV.

Dirk Gently episode 1 review

The show didn't have faith that its audience could either keep up with the plot or put up with more than a sprinkling of Douglas Adams' exquisite weirdness, making it difficult to have much faith in Dirk Gently in return.