The clock is already ticking when six Drug Taskforce detectives bunker down in a briefing room inside the secure Crime Command headquarters to plan a sting operation they hope will result in the seizure of drugs worth millions and the arrest of the key importers.
There will be no time for lengthy investigations because a two-tonne shipment is already sitting on the docks, with a second on its way from China. If the alleged crooks are not soon told they can pick up their consignment, they may suspect police have been tipped off and abandon the importation.
Sitting in the grey shipping container on the docks are ten 200-litre barrels of the industrial solvent 1,4-Butanediol that is to be sold in tiny fish-shaped soy sauce bottles as the drug GHB.
On the whiteboard in the briefing room under the codename Operation Aquatics 2017 are the names of two targets, their dates of birth and a checklist of requirements that need to be carried out before the arrest date.
They are all in "scruffs" - casual clothes detectives wear when they are working in the shadows - police lanyards around their necks the only sign of their true occupations.
The head of the operation, nicknamed "Keg", tells his crew one of the targets has a firearm licence and possesses two guns. A second suspect has a prior conviction for assault after he flogged a motorist following a minor car accident. Everyone is relaxed. The adrenaline surge will hit much later, during the arrest phase - that is if all goes to plan.
The raids will be planned knowing the targets may be armed and volatile. Whether the two are fronts for a known drug ring is a matter still under investigation, but what is clear is that you don't import such massive shipments without buyers and a distribution network already in place.
The team knows the syndicate has set up a fake cleaning company to make it appear the solvent has been imported for legitimate industrial purposes. The four-tonne order has been split in half, using two import brokers and two Chinese chemical manufacturers. Yet both shipments are to be delivered to the same business address.
The syndicate has set up the company with an active, if basic, website to appear operational. It would pass a cursory glance - but police investigations show it has no clients.
This group and many others are exploiting a ridiculous loophole in the law that the federal government has failed to address, in an act of blatant stupidity that is impossible to defend.
While it is illegal under state law to possess "Bute", as it is known, for human consumption, it is not illegal to import it for industrial purposes under Commonwealth law. This means criminal groups are freely importing the stuff and flooding the market, targeting nightclubs and music festivals.
Industry sources say 1,4-Butanediol is not an effective cleaning agent but a compound used in the manufacture of specific synthetic products. It would be simple to make it a substance that can only be imported under licence for manufacturing purposes.
And so it would seem that while the government has been determined to stop the boats carrying asylum seekers it is not so keen to stop them carrying an illicit product responsible for thousands of overdoses.
When swallowed, Bute is turned into GHB by the liver, but as the process is slower, users often take a second or third dose - resulting in a massive number of overdoses.
Most users are told they are buying GHB or Liquid E or liquid Fantasy, not an industrial solvent that suppresses heart and respiration function, particularly when used with alcohol.
Virtually all overdoses reported to be GHB-related are actually caused by Bute, although pathology tests cannot differentiate between the two. And police say Bute is now the date rape drug of choice, sweetened with a touch of cordial to mask the bitter taste.
The profits are massive. Imported for $7000 a barrel, 200 litres of Bute can be sold immediately for a wholesale price of $200,000, which means the four-tonne lot is worth $4 million. In the retail market, where Bute is sold for between $7 and $15 for 3 millilitres, the profits are astronomical.
If all this Bute made the market, it would be the equivalent of 1.3 million doses, with a street value in excess of $15 million.
The first shipment has been discovered on the docks by Border Force officers, who then contact Victoria Police. Bute is not considered a high priority, as it is not a prohibited import - even though it is clearly being used as an illicit drug.
Which means the Border Force officers are going beyond their usual duties of concentrating on illegal imports to assist Victoria Police in dealing with what has become a massive problem. "They have been incredibly helpful to us and without them these big shipments would get through," one of the Aquatics team says.
In the last three years, police have discovered just 10 ml of GHB and the latest operation will bring the Bute seized in Victoria in the same period to 19 tonnes. That is well over six million doses - and still the federal government has failed to act.
Let's put this another way. Police are seizing nearly two tonnes of Bute, a GHB alternative, for every one millilitre of real GHB. And yet the importation of Bute gets the green light, while GHB is banned.
Certainly there is intelligence that some of the profits have ended up in the hands of terror suspects, while some are assigned to pay the legal fees of charged drug traffickers.
Just recently two sitting judges independently expressed concern about Bute, saying they were alerted to its widespread use by previous stories in this column. We reflect on this not to pump up our own tyres (some critics say they have already reached monster-truck proportions) but to show the lamentable lack of a co-ordinated public policy on what has become a gold mine for organised crime.
At the briefing for Operation Aquatics, the team prepare to notify surveillance police who will be needed for the controlled delivery and the undercover unit that may be required if the job gets complicated.
The team assign a list of tasks, including swearing out affidavits and warrants, then prepare for the secret drug switch. The sting is on. They source near-identical barrels for the substitution that are then filled with water by Fire Brigade high-pressure hoses.
The next day the container is opened inside a warehouse and the real stainless steel drums, clearly marked as "1,4-Butanediol Made in China" and wrapped in protective plastic film, are removed by forklift and replaced with the fake police ones.
The real Bute is then sent to the lab to be analysed and will be destroyed at a later date.
The team speculate that a recent increase in the large number of importations is due to gangs stockpiling the product, believing the legal loophole will soon be closed. "They want to get in first," one says.
"And we are coming into the party season," another adds.
While police can plan for different contingencies, once the switch is made it is the suspects who unwittingly control the operation, as the team can only respond to their movements. It becomes a waiting game.
Will they want to pick up their own importation or require it to be delivered? Will they use unwitting drivers or syndicate members? Will new suspects turn up? When and where will they take the barrels, or will they be spooked and fail to show?
Eventually representatives of the cleaning company make contact with the importers to say they will pick up their own consignment, nominating a two-hour window on a weekday.
We enter the arrest phase.
The suspects are late, but as a rule crooks are rarely punctual. Three men arrive at the docks in a rented truck and pick up the drums, sitting on three wooden pallets. They take them to a private property on the outskirts of Melbourne and unload them in a garage.
But soon a second van becomes involved. For the next 24 hours, the suspects are followed as they stop at several addresses that police will only say are known to them.
The targets are tracked through Melbourne's north-western suburbs until Wednesday night. Just one week after the initial briefing, around 15 Drug Taskforce detectives backed by uniformed police move on a residential home in Melbourne's outer north. Two men are arrested in a car and a third at the front door without incident.
Three registered firearms are seized along with documents relating to the importation. The property where the fake Bute has been housed is also raided.
The suspects are interviewed and maintain they have ordered four tonnes of Bute for legitimate industrial purposes.
They are released without charge as inquiries continue.