Anticipating a showdown with Iran, Israel decides secretly to deploy a submarine off its arch-foe's coast.
But how? The quickest route from Israel's Mediterranean coast is via the Suez Canal, which runs through Egypt and which the classified vessels shun. So the submarine is hidden in the belly of a commercial tanker, which delivers it to the Gulf.
Such is the plot of an Israeli thriller, "Undersea Diplomacy". Does it hold water? Perhaps not. Then again, the author, Shlomo Erell, is no mere novelist. He's an ex-admiral with experience in Israel's most sensitive military planning.
"It's pure fiction, but it's informed fiction," he said simply, when asked if his book reflects how the Israeli fleet of Dolphin-class submarines could be used against Iran, whose leadership has called for Israel to be "wiped off the map", stoking international concern over Tehran's nuclear programme.
Israel has three Dolphins, with two more on order from Howaldtswerke-Deutsche Werft, a German shipyard custom-building them at a steep discount as part of Berlin's bid to shore up a Jewish state founded in the wake of the Nazi Holocaust.
The submarines are a subject of deepest secrecy given speculation that they carry nuclear-tipped cruise missiles.
Many analysts believe the Dolphins are Israel's "second strike" weapons, referring to the Cold War theory that a country can deter foes from launching nuclear attacks by maintaining the ability to retaliate, even after its own territory has been laid waste. A nuclear "platform" out at sea is the best guarantee.
Iran denies seeking nuclear weapons, and independent experts say it is years away from any such capability. Some, in turn, think Israel's expanding submarine fleet may be part of preparations to foil the perceived future threat through force.
"There is nothing on the horizon to suggest Iran would have the capability to knock out Israel's nuclear delivery means," said Sam Gardiner, a retired U.S. air force colonel who stages Middle East wargames for U.S. government and private clients.
The Dolphins, he said, may be part of "a conventional capability to deal with the number of targets Israel believes would need to be struck in a conventional preemptive attack".
DISTANCE NO OBJECT?
Israel sent jets to bomb Iraq's nuclear reactor in 1981 and has hinted it could do the same against Iranian facilities if U.S.-led diplomatic pressure failed to rein in Tehran's plans.
But the Iraqi raid was on a single site, relatively close to Israel's borders. Targets in Iran might be too numerous and distant for Israel's air force, especially as intermediate Arab states or Turkey would likely refuse overflight rights.
Israel is assumed to have ballistic missiles, yet its small size may make surprise launches impossible: an unannounced missile test in January became news within minutes as the startled residents of nearby towns reported the roaring takeoff.
Submarines could bridge the gap, especially if positioned in Iranian waters. That possibility has given rise to speculation that Israel wants five Dolphins in order to allow for at least one to be at sea at all times while others are being serviced.
The question remains of how far they might travel.
Israeli navy sources say the Dolphins do not use the Suez -- to avoid being inspected by Egyptian harbourmasters. That means that, to reach the Gulf, Israel would either have to resort to fantastical ruses like the one in "Undersea Diplomacy", or send the submarines around Africa -- a month-long trip at least.
Jason Alderwick, a maritime analyst with the International Institute for Strategic Studies in London, is sceptical.
"I don't buy the idea of a rotation. These submarines have not been purchased with a view to operating in the Gulf," he said. As Dolphins run on conventional rather than nuclear power so require regular refuelling and shore maintenance, he described them as better suited to close Mediterranean missions.
Israel also has access to the Red Sea through Eilat port. But navy sources said there was no plan to dock submarines there because the narrow Red Sea, which is shared with several Arab states, is vulnerable to blockades at the Straits of Tiran.
DETERRENTS NEVER USED
Restricted to the Mediterranean, analysts point out, the Israeli Dolphins could pose a "second-strike" threat to Iran only if they carried nuclear cruise missiles capable of hitting targets as far as 1,500 km (970 miles) away.
Lee Willett of the Royal United Services Institute for Defence and Security Studies noted that Dolphins lacked the vertical tubes used by much bigger Western and Soviet-era submarines to launch ballistic missiles.
Cold War tests showed nuclear warheads are too heavy to be delivered long distances on cruise missiles, so Israel could hit Iran only with conventional warheads if they were fired from the Mediterranean, he said.
A nuclear attack on Iran by a Dolphin, Willett argued, would have to be from the Gulf, which in turn would give away an unsupported submarine's position and probably doom it to being destroyed by surviving Iranian forces.
"The whole point of a deterrent is that it's never used," Willett said. "In designing the Dolphins as a second-strike platform, I imagine the Israelis were thinking 'it's not ideal, but it's the best we've got'."
Israel does not discuss its nuclear capabilities, under an "ambiguity" policy billed as warding off regional enemies while avoiding the kind of provocations that can trigger arms races.
Erell appeared to support such thinking. The message of his book -- which made a modest splash in Israel, and is currently available only in Hebrew -- was "how to use a submarine without resorting to war". "It's about affecting statecraft," he said.