Ludwig review: David Mitchell excels in this mix of puzzles, laughs and cosy crime

I was thinking about these issues while watching Ludwig (BBC1, Thurs, 9pm) every time gravel-voiced Ralph Ineson popped up on screen as Chief Constable Ziegler, the current nemesis of crossword setter-turned police impersonator-turned crime scene consultant John Taylor (David Mitchell).

Ineson, you see, played villain Galactus – the big purple bloke - in the recent Marvel movie about the Thing and his pals. The only problem is that, while thinking about Reed Richards and exactly which bits stretch and which bits don't, I got a little bit lost when it comes to the plot.

This week's episode of the crime comedy-drama picked up almost immediately after the first series finished, with John – who uses the name Ludwig on his puzzles - trying to work out why his twin brother James disappeared, with the help of sister-in-law Lucy (Anna Maxwell-Martin) and nephew Henry (Dylan Hughes).

Put there's also a murder of the week to fit in around the ongoing story arc, this week seeing a unpleasant old bat murdered in the box of the theatre with the only two suspects each claiming they did it and the other is innocent.

Of course, John solves the crime after a lot of “but that’s impossible. Or is it?” chat and the bag guy goes to jail.

This could all be a but ho-hum, a bit Death in Paradise, but it's better done than that with the reveal particularly shot beautifully, all Ludwig's heightened imagination shown in surrealistic tableaux while he stands on the stage at the theatre.

And while you can work out the mechanics of the murder, the precise details still do come as a surprise.

Meanwhile, there are lots of comic bits of business, particularly with John getting sweatily-nervous on a car journey with the chief constable, while his relationship with Lucy is lovely, his more worldly sister-in-law getting exasperated with the bumbling brother.

It could all be as light as air, forgettable, but the ongoing mystery about John's twin brother deepens the plot, and while Mitchell as John provides most of the laughs, Maxwell-Martin provides the emotional heft, never letting you forget the hole that her husband's disappearance has left in her family's lives.

This new series adds further texture, with Lucy getting a job at the local paper – mainly to gain the press card which would give her licence to poke around in other people's business.

Mark Bonnar plays the newspaper's editor and it's one of the only series I can remember which accurately depicts staffing levels at a local paper – the office is deserted.

Meanwhile, two new police officers are added to the cast, which means they get to marvel afresh at John's puzzle-solving abilities and not ask awkward questions about why he's at their crime scene.

This new series promises to deliver much of what the first one won so many fans for, but it does deepen the plot with hints of police corruption and the involvement of the local MP, played by Fleabag's Sian Clifford.

And that central relationship between John and Lucy is a terrific peg to hang the whole thing on, the sparring between them putting you in mind of a 1930s screwball comedy.

It's quite something when a BBC comedy show can put you in mind of a purple super-villain and Cary Grant looking after a leopard.

But then Ludwig is a cut above the run-of the-mill – it takes all the usual tropes and adds an extra sheen of inventiveness, comedy, quality. Now, if he could only explain why the Human Torch doesn't burn his clothes.