David and Carlos are still in Cuba and have found the exact same species that is devastating Charringa's crops in Florida. David is trying is best to hide this from the US government so that they do not decide to bomb Cuba. They send all their samples to Mayko without anyone knowing so that she can use the technology Norbac has to analyze the bacterium. What they did not count on is some announcement that Norbac has found that the bacterium is coming from Cuba. Neither Caroline, nor David know where this is coming from and Connor McGuinn is trying to stop the US government from deciding to attack Cuba as Norbac never established that at the time of the announcement.
Caroline, Bob and Simon do more tests on Glenn and Simon believes that the next step is to do brain surgery so that he finally emerges.
Jill asks Mayko to contact all the labs using the Korean stem cells to know if they found a retrovirus in the stem cells. The reactions is immediate and all the labs insult Norbac. Bob, then, offers to verify the procedure Jill follows and he finds the difference between her analysis and the other labs, she makes her own kit while the other labs use a standardized kit and that is why the retrovirus never shows on their results. Now, Jill needs to find if the retrovirus is harmles or if she can deactivate it so that the cure she found for diabetes can actually be used.
Mayko sends her results to David and Carlos who are still in Cuba, she tells them that the new bacterium they have is definitely different and has been engineered. They found a marker that is supposed to make the bacterium harmless except it is doing the exact opposite. On a hunch, David asks Mayko to search if the marker was patented and they trace it back to a university professor in California. The professor explains to David that it was engineered for grapes. David then realizes that Cuba has nothing to do ith what happened to the lemon crops and they go back to Charringa's property in Florida where they meet Connor McGuinn.
At Norbac, Owen shows up and asks for Jill's help, he needs a place to stay for a few days and she takes him to David's apartement.
David and Carlos meet with Charringa and ask him if he vaccinated his trees with the bacterium used for protecting grapes. Charringa then realizes that his second in command vaccinated all the trees for the purpose of exporting lemons ; Charringa realizes that he is responsible for the destruction of his own crops.
David gets back home and find Jill and Owen at home, he is not too hapy about it. He wanted to be alone with Jill but he agrees to let him sleep on the couch.
The brain surgery on Glenn was a success and they try to communicate with him by spelling each lette rof the alphabet. As they write down the letters, the message starts to be clear. Glenn asks Caroline to let him die and she agrees.
A friend of Bob sends some pictures of clouds over Mexico and Bob realizes that his Asian brown cloud is over Mexico, he asks Mayko to recontact his friend to monitor the cloud as he thinks this maybe a massive climate problem for Mexico.