Further than the Furthest Thing is an allegorical play set on a remote island populated by English-speakers from all over the world. Dialect experts will have a ball unscrambling the set-up. First we meet Auntie Mill, a white Scotswoman whose husband, Uncle Bill, is a black fisherman with a West Country accent. Their nephew, Francis, is a mixed-race teenager whose verbal mannerisms seem to originate from North Yorkshire. And he has a pregnant girlfriend, Rebecca, who looks east Asian but talks like a Dubliner. This crazy muddle may be a deliberate assault on the entire cult of colour-blind casting. Or it could be a thoughtless embrace of chaos. Either way, it’s baffling to watch. Theatre is all about resemblances and the closer the resemblance, the more successful the play. That’s why actors wear costumes and wigs. If imitation dies, so does artistic truth.

The show’s storyline is equally inscrutable. The opening scenes introduce us to a community of simple-hearted crofters who scrape a meagre living from poultry and haddock. When Francis returns home from South Africa, he brings with him a charismatic millionaire, Mr Hansen, who wants to build a crayfish plant on the island. Uncle Bill, who acts as chief planning officer, opposes Mr Hansen’s scheme but the rules change at the last minute and Francis is given the casting vote. He sides with Uncle Bill and betrays Mr Hansen. And yet Mr Hansen doesn’t punish Francis for his treachery but continues to employ him.

In this parallel world nothing makes sense, and in order to stay involved in the narrative you have to abandon your attachment to logic – just as you might when listening to an anecdote recounted by a five-year old. The writer, Zinnie Harris, sets out to create a story with the strangeness, sweep and grandeur of a child’s fairy tale and she succeeds.

What the allegory means is harder to say but the plot keeps changing tack and delivering big emotional surprises. A corny trick but it always pays off. After the interval, the crowd had thinned out a bit and the story was running out of oomph. The islanders had been shipped off to a nameless city in England where they worked at a new factory owned by the unfathomable Mr Hansen. Rumours about a volcanic eruption on the island began to spread but they were countered by suggestions that the eruption had been hushed up. (How do you keep a volcano quiet? In this show anything’s possible.) By this point a few more play-goers were heading for the exit, in full view of the cast, but perhaps they were impatient to discover what the show was really about.

According to the Young Vic website, the story refers to Tristan da Cunha in the south Atlantic whose residents were evacuated in 1961 after a nearby volcano went pop. That’s as much as the website tells you. So this is a history lesson of a very peculiar kind. You have to study the events in advance. Then you have to watch a dramatised tutorial about the events you’ve researched, but you won’t learn anything new because this is an arty, balletic dreamscape full of cryptic symbols and references. Someone hasn’t thought this through.

Nicholas Hytner’s latest show is a big, sprawling razzmatazz version of Guys and Dolls. The script, collated from short stories by Damon Runyan, is set in a charming New York underworld populated by comedy gangsters with names like Harry the Horse and Dave the Dude. No one poses the remotest danger to anyone else. It’s like a Scorsese movie with all the characters cracking jokes and firing blanks.

The script introduces us to a professional gambler, Sky Masterson, who wants to lure the beautiful Sergeant Sarah away from her job at the ultra-religious Save-A-Soul mission. The comedy emerges from the collision between two conflicting moral codes: puritanical Christianity and preening criminality. To win a bet, Sky asks Sarah to join him for a date in Havana but she’s a follower of Jesus so she turns him down.

Their affair is contrasted with Adelaide and Nathan whose lengthy engagement has yet to be sealed at the altar. But Nathan has lied to his relatives about Adelaide and he writes to his mother boasting of their growing ‘family’ and their five fictional kids.

This a ripping production with plenty of laughs and a superb design by Bunny Christie. A word of warning. The action takes place in a crowded mosh pit and the actors perform on moveable blocks that get pushed around by busy technicians. The spectators get pushed around too and if you don’t enjoy being herded this way and that, like a Gatwick tourist, you can avoid the mayhem by booking a comfy seat in an upper gallery. You’ll be further from the action but at least you’ll dodge the cattle-prod treatment.