The Sabbath normally starts around seven o’clock on Friday afternoon and finishes at a similar time on Saturday. More specifically, and if we’re true to the guidelines contained in the Talmud, only after three stars have appeared in the night sky. In this one-day timeframe — during which, in the Western world, a huge number of social events normally take place — Tel Aviv is seriously limited. Not for everyone, however, as we shall discover later.

Rabin Square and its sumptuous ponds flank the City Hall, where Ben and Myriam worked on a range of different tasks. Friends since their teenage years, they had done military service together and both found employment in the public sector. Ben specialised in town planning and Myriam, the environment.

Both knew that it was the architect Patrick Geddes who had been commissioned to design the city in the early years of the last century. He had applied Bauhaus principles (functionality, accessible materials) and other concepts so that residents would feel part of a community. The area of almost four thousand buildings designed in line with Bauhaus aesthetics, still standing in Tel Aviv, has been declared a World Heritage Site, which made Ben feel especially proud.

Singing, dancing and making bonfires by the cliffs along Banana Beach are among the favourite pastimes of young people in Tel Aviv when the sun starts to set. The Mediterranean bathes these golden beaches situated close to Jaffa, in the south of the city. And just few minutes from here, across the wide Bograshov Street, is the Bauhaus Centre, the operational base for the real protagonist of our story.

The suffocating temperatures in the month of May make it the least popular for tourists but the time of year when locals are most enthusiastic for any kind of activity that helps to cool down.

That’s why, after a long week at work and before the start of the Sabbath, Ben and Myriam had decided to chill out at Banana Beach. Sabbath paralysed the city to a great extent, although the impact varied from one neighbourhood to another. And as a complete contrast, there was the splendid atmosphere at Banana Beach. Countless drums beat in synchrony while people swayed to rhythms that seemed to fuse the soul of the Caribbean with the ancient cultures of the Mediterranean.

Numerous barbecues impregnated the air with a sweet, appetising smell and a whole range of products, many of which were far from kosher, sizzled away on the grills. There was even a group of American tourists flame-roasting pork ribs, Cajun-style. The mystery is where they had acquired their raw materials… Perhaps squeezed into their checked-in luggage in the aircraft’s hold?

The two friends took along an icebox packed with near-frozen drinks in order to combat the heat between one swim and another. They were just installing a huge parasol when a commotion in the far south of the beach began to spread their way like wildfire, accompanied by confused yelling.

“What’s happening? Look at those people, they seem to be running this way,” Ben said to Myriam.

“Sharks! Sharks!” shouted one of the young men, rushing towards them.

“Here, in the Mediterranean?” asked Ben, incredulously. At which point Myriam put her expertise into action.

“In the Mediterranean there are over forty species of shark, darling, although there have been no sightings so far in Israel. These figures include the legendary Carcharodon carcharias or Great White Shark, which sneaks in through the Straits of Gibraltar and can even reach the Black Sea. So why not Tel Aviv?”

“Well that has really calmed me down…” replied Ben, nervously.

“What exactly did you all see?” Myriam asked one of the terrified surfers.

“A dozen fins that cut through the water at high speed, like knives.”

“A dozen? That’s weird. I don’t think they’ll be white sharks then… Probably makos. The Isurus oxyrinchus can swim at over 100km per hour. It’s impossible to overtake them, even in a speed launch. And they can jump right into your boat too. As far as I’m concerned, the size of their jaws and their four metre length make these sharks much scarier than the whites.”

“They worked together, until the last terrified bather or surfer got out of the water. They targeted a couple who were kissing on top of an inflatable sun lounger.”

“Kissing?” laughed another surf girl mischievously. “If we’d had a mobile with a zoom lens we could have filmed an adult movie, one of those that they broadcast on the pay per view channels in hotels.”

“Maybe these are moralistic sharks…” added the first surfer with a touch of sarcasm.

“I think I’ve heard enough,” said Ben, in a serious kind of tone. “Shall we head back to the city centre? I don’t feel like dancing any more and…”

“On the Sabbath?” Myriam cut in. This beach is much more fun, even with sharks!”

Not very far away, surrounded by computers, screens and other cutting edge devices, Rabbi Slomo Jacobo Kowalski had built a small capsule room from which to remotely control the sharks. Each of them was fitted with a camera and the rabbi could manage their speed and direction.

His aim was to scare beachgoers and ensure compliance with religious rules. He didn’t approve of young people playing instruments, drinking alcohol and behaving immodestly between the sand dunes at the beach. Or on a lounger. And even less so on a Friday afternoon when the Sabbath had already begun. And in terms of the barbecued pork… Well, he was forced to restrain himself to avoid blaspheming and pronouncing phrases that he would later be obliged to atone for at Yom Kippur.

Rabbi Kowalski, before becoming a rabbi, had been an engineer, soldier and Mossad agent. It was a CV that could have triumphed on the pages of a John Le Carré novel. And he had participated in a secret programme to remotely deploy explosive-carrying dolphins against any ship that could pose a threat to Israel.

His tactical and technical how-how had led the rabbi to develop a small armada of sharks that were operated in a similar way to drones but in unison, as if he was managing just one creature. Kowalski’s fearsome squadron of Isurus oxyrinchus was made up of twelve beasts, each of which had been fitted with the requisite transducer chips through a number of well-aimed shots. Twelve were the tribes of Israel, which is why the sharks had been given their names: Reuben, Simeon, Levi, Judah, Dan, Naphtali, Asher, Gad, Issachar, Zebulun, Joseph and Benjamin.

The Twelve Sharks were only called into action on Friday evenings, carrying out their purifying tasks through to the end of the Sabbath on the following day. During these 24 hours, the rabbi didn’t get a moment’s sleep, especially when Banana Beach filled up with impious crowds.

When the Sabbath was over he headed for the beach in person, even rolled up his sleeves and ventured into the water almost up to his waist. He called out to his children with a hugely sophisticated, waterproof remote control device. And the sharks obediently came to him, forming a semicircle around his imposing, Messiah-like figure.

One day, however, the batteries in the remote control were flat…