A powerful drug lord, Franz Sanchez controlled the South American city of Isthmus, having either bribed or killed all of its lawmakers and politicians. In particular, he had President Hector Lopez under his thumb, as well as his own private army commanded by his head of security, Colonel Heller. Sanchez also had in his employ Milton Krest and Professor Joe Butcher, who ran two fronts in the drug lord's empire, as well numerous other assorted thugs, goons, and hitmen, including the shifty Truman-Lodge.
He was fond of saying, "Loyalty is more important to me than money," making him one of few villains who realized that a happy henchman was a loyal henchman; he paid his underlings very well. But because loyalty was so important to Sanchez, he could become very volatile and paranoid whenever he suspected someone of swindling him. This was best seen when his girlfriend, Lupe Lumora, who had been cheating on Sanchez with his "friend" Velasquez, was caught by her boyfriend while in the Bahamas. Sanchez punished Lupe by brutally whipping her with a stingray tail, and administered an even horrific fate to Velasquez.
But coming to the Bahamas set in motion a chain of events that would finally bring Sanchez down. As long as he remained in Isthmus, Sanchez was safe from the DEA because they could not extradite him. However, so furious was he at Lupe's infidelity that he had to personally come and retrieve his errant girlfriend. Once outside Isthmus however, he was quickly set upon by DEA agents who were being assisted by James Bond and Felix Leiter. But instead of going to jail, Sanchez was set free en route to Quanico by his guard, Ed Killifer, after promising him $2 million in cash. And because of his philosophy of loyalty above all else, he made good on his promise and paid Killifer the money once they'd reached the safety of Milton Krest's warehouse.
Before returning to Isthmus, Sanchez decided to first get revenge on the man who he believed was most responsible for inconveniencing him: Felix Leiter. He sent three of his hitmen, Dario, Perez, and Braun, to abduct Leiter from his home. They did so, raping and killing Leiter's wife Della in the process. When the three returned to the warehouse, dragging a tied-up Leiter with them, Sanchez revealed he intended to feed him to Krest's pet tiger shark, which was kept in a tank hidden under the floor. At the push of a button the trapdoor opened and revealed the water with the shark below, and Leiter, tied to a hook, was lowered in. "See you in hell!" he vowed. But Sanchez said there are "worse things than dying," and orders him pulled back up... after the shark had eaten his legs off.
That accomplished, Sanchez had his men drop the wounded Leiter off back at his house, then went back to Isthmus by way of Krest's ship, the WaveKrest. With the Leiter incident behind him he was ready to put into motion his plan to expand his drug empire by making a business deal with several Chinese crime lords. Meantime, James Bond had discovered what Sanchez had done to Leiter and, after having his licence to kill revoked, set off on a personal vendetta against the villain. He turned up at Sanchez's casino in Isthmus after stealing a vast amount of money from Krest, and luckily for him Sanchez only got fleeting glimpses of him in their encounter when he was arrested. As did Perez and Braun, who were also present and make sure to frisk Bond when he came in. As did Perez and Braun, who are also present and make sure to frisk Bond when he comes in. Equally lucky was that Dario, who had encountered Bone when Sanchez sent him to kill Leiter's colleague Pam Bouvier, was off somewhere else running another errand for his boss (acquiring stinger missiles, to be exact).
All this means that Bond was in a perfect position to make nice and become friends with Sanchez in order to get close to him. Offering his services as a "problem eliminator," Bond got on Sanchez's good side by "helping" to root out several traitors in his organization. The first was Kwong, one of the Chinese crime lords who was really an undercover agent from Hong Kong, and the second was Krest, on whom Bond pinned the blame from one of his own failed assassination attempts on Sanchez. He served up for Krest the nastiest death of all, stuffing him into a pressurized diving chamber and turning up the pressure until Krest's head swelled up and exploded into a bloody mess.
Afterward, Sanchez decided to take the Chinese drug lords on a tour of his drug labs to show that he was legit, and, impressed by Bond, decided to let him tag along too. Unfortunately Dario had picked that day to return with the stinger missiles in tow, and he turned up at the factory and immediately recognized Bond. Bond then got into a fight with Dario, Perez, and Braun, which resulted in the lab being set on fire. The fire couldn't be brought under control, and the factory, loaded with flammable stuff of all kinds, was threatening to blow off the face of the planet any second. Firstly, Sanchez ordered Colonel Heller to mobilize the four tanker trucks that had twenty tons of cocaine in them to save them from the fire. Next, he had Dario and Braun drop Bond on a conveyor belt that would drop him into the machine that ground up the coke.
Accompanied by Braun, Sanchez then went to retrieve the stinger missiles. He found Heller in the process of stealing them, and so had Braun kill him by impaling him on a forklift. With the stingers, the villains began to flee the burning factory en masse: Sanchez and Truman-Lodge in Sanchez's luxury sedan, Perez and three anonymous thugs in a Jeep, Braun in a pickup truck all by his lonesome, and then the four tanker trucks. Piloting a crop duster, Pam Bouvier flew Bond (who naturally had escaped from the crushing machine) over the convoy and dropped him off onto the tanker that was bringing up the rear. Getting into the cab, he overpowered the driver and throws him out. Sanchez drove on ahead and met Perez had a designated spot, giving him one of the stinger missiles with which to blow Bond to kingdom come before driving on.
This fails and Bond unhitches the trailer, letting it roll down the hill and smash into one of the two remaining tankers as they drive down the mountain, resulting in a mighty explosion. Because his car was bringing up the rear and the destroyed tanker sat between him and the only remaining one, Sanchez had to abandon his car and cut around the fire on foot. But not before he blew Truman-Lodge away for insulting him, naturally. Sanchez and his portly chauffeur, in the only remaining tanker, are forced to stop when Bond, who was right behind them, boarded their vehicle while they were in motion, undid the valve, causing the cocaine-tainted gasoline to leak all over the road. Sanchez came after Bond with a big knife, and somehow or other cuts the brakes of the truck, causing it to roll forwards off a cliff with the two men still holding onto it and fighting.
Amazingly, the tanker did not immediately explode but merely cracked in half, spilling gasoline everywhere, including on Sanchez. He held Bond at knifepoint and prepared to kill him, when Bond whipped out the gold lighter which Felix and Della Leiter had given him at their party. Using it, he set Sanchez on fire. The flaming drug lord then stumbled into the crashed tanker, and Bond fled as the vehicle exploded.