- "My sources are convinced there's a plot in International Affairs, y'know 'The Agency', and they're using this facility to make a serious nerve toxin...Yeah. Which they plan, in their mind blowing insanity, to let a major terrorist release on a metropolitan area, so they can continue to get funding."
- ―Steve Haines
Michael, Franklin, and Trevor meet at Cape Catfish. Soon, Steve and Dave Norton arrive. Steve wants the protagonists to steal a chemical weapon from the Humane Labs and Research, an IAA research facility. Due to a lack of manpower, Steve and Dave join the caper. Steve instructs Trevor and Franklin to handle transport, while Michael joins Steve and Dave in infiltrating the lab.
Michael, Steve, and Dave, dressed in scuba suits, take a Dinghy down the San Andreas coast to a spot near Humane Labs and Research. The three dive and approach an underwater exhaust shaft; to gain entry, the player as Michael must use a torch to cut loose a grate over the shaft's access point. Once inside, the three swim through the shaft until they reach the interior of the lab. From there, the three advance through the halls. Michael is armed with a stun gun and is responsible for taking out the scientists and other employees encountered along the way.
Soon, the three reach their destination. After convincing a scientist to open the lab door, Michael is able to grab the chemical weapon. An alarm is triggered and armed security guards begin to appear. Michael and the two FIB agents push through to the lab's garage area (Michael is now encouraged to use his regular arsenal). Outside is a refrigeration unit meant to transport the chemical weapon; Michael places the weapon in this container.
The player is shifted to Trevor flying the Cargobob Steve purchased with the money taken in The Paleto Score. Trevor lowers the Cargobob over the refrigeration unit. However, Steve suddenly insists that the heat is too great and that they call off the operation. Michael argues. Steve soon relents. He runs back into the lab's garage; there, he shoots himself in the leg, then presents himself as a hero to the arriving security agents. However, the United Liberty Paper Contact dosen't buy it and orders Hains to be detained.
With refrigeration unit in tow, Trevor flies to Sandy Shores Airfield, lowers the container onto a waiting Flatbed, then lands the helicopter. Franklin and Michael confer with Dave, who then leaves with the semitruck. After Dave is gone, Michael checks his phone and sees that Martin Madrazo has accepted as apology the artifact Michael and Trevor stole in the mission Derailed. Michael celebrates with Franklin, excited that he can finally return to Los Santos
The player is shifted to Trevor as he drives Patricia back to her husband. The radio in Trevor's Bodhi is automatically set to Los Santos Rock Radio, with "If You Leave Me Now" by Chicago setting the appropriate mood. As they drive, Patricia tells the crying Trevor that she will miss him but that this is for the best. Trevor leaves Patricia at Madrazo's mansion at La Fuente Blanca, but not before threatening a clearly frightened Martin. At this point, the mission ends.
- Navigate down to the coast line. - (Michael)
- Gain entry to the lab. - (Michael)
- Go to the elevator. - (Michael)
- Incapacitate the lab workers. - (Michael)
- Take cover from the security guards. - (Michael)
- Get the nerve toxin. - (Michael)
- Take out the security guards. - (Michael)
- Put the nerve toxin into the refrigeration unit. - (Michael)
- Collect the container. - (Trevor)
- Fly to the airfield. - (Trevor)
- Land the crate on the trailer. - (Trevor)
- Land the helicopter. - (Trevor)
- Drive Patricia to the farm house. - (Trevor)
Gold Medal Objectives
- Stunner - Stun 8 enemies with the Stun Gun.
- Headshots - Kill 15 enemies with a headshot.
- Accuracy - Finish with a shooting accuracy of at least 70%.
- Time - Complete within 13:30.
Weazel News Newspaper
"A violent break in at a biotech lab in the San Chianski Mountains ended in bloodshed, mayhem and the loss of a formula for cheap perfume. The meticulously planned raid appears to have been carried out by highly skilled professionals, as thieves swam into the facility using diving equipment to access an underwater drainage pipe. Several research scientists and security personnel were killed at the facility which has been attacked by animal welfare activists in the past. The facility was once believed to have been a testing center for chemical and biological weapons, but those rumors have long been dispelled and now the facility tests soaps, high tech face creams and cosmetics. Agents are baffled as to the scale of the raid, as the perfume formula stolen was not considered particularly valuable."
- Tracey De Santa - "Hope you're taking care of yourself, Dad. I know what a magnet for absolute chaos you are."
- Amanda De Santa - "I hope none of this stuff I'm seeing on the news has anything to do with you."
- Tracey De Santa - "If it makes you feel any better, Fabien is a real douchelord."
- It is later revealed via a Weazel News radio broadcast that the "dangerous chemicals" were really a new recipe for "cheap perfume" (though this is likely a cover story).
- However, it is to be noted that after the chemicals are delivered to the trailer, Michael says that "...It could be shaving cream for all I know."
- When taking Patricia Madrazo back to her husband, the radio will automatically be tuned into Los Santos Rock Radio playing "If You Leave Me Now" by Chicago.
- The Jetsam Cargobob can be obtained in this mission, the Jetsam edition of the Cargobob is rare, because the chopper is in white and red, while the Cargobob only comes in two variants: Camo, and black. It also doesn't have the Sea Stallion (part of what the Cargobob was made from) "buff" in the front. It can be obtained by first dropping the container on the trailer, and NOT landing the Cargobob in the given location. And try to shove the Frogger off the helipad, but be warned it may explode. After the Frogger is off the helipad, land the Jetsam Cargobob, and kill yourself (as Trevor.) And when it says to replay this mission, select no, and then when you are recovered from the hospital, RUN to the Sandy Shores air field, do not drive or take a cab, the chopper should still be there, like you left it, and it can be saves on the helipad, provided the player doesn't change helicopters, or the Jetsam Cargobob will dissapear. This method also works with the Cargobob stolen from the military base, (if the player chose option B for the Merryweather Heist. Offshore option) although doesn't involve killing yourself, just land on the helipad, get out of the Cargobob, and run away.
- While traveling through the secret passage, Michael says that he feels like he's giving the Statue of Happiness a colonoscopy.
- The mission's name is likely a reference to the Cary Grant/Marilyn Monroe movie of the same name. The movie focuses on a chemist whose chimpanzee inadvertently discovers a youth serum. The mission involves the raid of a chemical plant, inside which the raiders find monkeys that have been used in experimentation.
- The entry duct underwater will have a secondary grate put over it after the mission to prevent the player from entering the facility again.
- Michael can call Solomon Richards after this mission, to tell him that he is back in Los Santos.
- Patricia Madrazo will make her first call to Trevor right after this mission.