Before The FAYZEdit
San Francisco de Sales is mentioned but not named during Sam, Astrid Ellison, Quinn, Edilio, and Little Pete's trip along the FAYZ Wall. It is identified despite not being named as Sam mentions "One of the islands had a yacht crashed into it."
In Lies, Caine and the remainder of Coates leave for San Francisco de Sales and take over the island. Sanjit and Virtue pretend that the island is really a Leper colony, and that they are the only ones on the island (they don't mention Peace, Bowie and Pixie). However, Diana quickly figures out they are lying, and they have no choice but to take them in. They give them food with medicine to make them fall asleep, while they then take Peace, Bowie and Pixie and leave by helicopter for Perdido Beach. Caine, Diana, Penny and Bug wake quickly (Diana finds that Sanjit didn't tie her up) and then realize that Sanjit and Virtue have left in a helicopter, but Caine sees them as they are rising, with three little children (Peace, Bowie and Pixie) that they hadn't mentioned in the back. Caine, angry at them for not telling him there were others, uses his power of telekinesis to hold the helicopter. When Penny offers to work her illusions on them, Caine takes her and puts her above the top of the helicopter. Diana, realizing that Sanjit and the others are good, threatens to fall off the cliff if he doesn't stop. She accidentally does fall, but Caine uses his power to stop her from falling, even if it means that Penny falls and the helicopter gets away. They find Penny later with both of her legs broken.
In Plague, Caine, Diana, Penny (still with her broken legs) and Bug live on San Francisco de Sales. They get used to the luxury of real food, hot baths and showers, and clean clothes. Caine and Diana are practically the Jennifer Brattle and Todd Chance of the FAYZ, or at least consider themselves that way. Finally, Quinn comes to tell about the Plague and the bugs infecting the town. Caine decides it is time for him to go back to Perdido Beach and make a heroic entrance, while saving the town. Diana is reluctant, however, because she had gotten used to the luxury. When the arrive back in town, Taylor is given the option to join with Caine and have access to the luxuries of teleporting to San Francisco de Sales island, which she accepts.
In the beginning of Fear, Taylor is at San Francisco de Sales and realizes that her skin has turned gold. She teleports back, trying to get to Clifftop, but gets stuck in a tree (much like Albert's Cat). She then teleports and lands halfway in a car, having lost both her legs and one hand. She is found by Sanjit and Virtue, but Lana is unable to heal her, since she is not a mammal anymore (she is now a reptile). By the end of the book, her fate is undetermined. San Francisco de Sales is then taken by Albert, when he abandons Perdido Beach to live on San Francisco de Sales with a few of his other people. He brings missiles from the power plant in case someone tries to get on to the island.
When the barrier becomes clear at the end of Fear, a lot of the children stay and camp at the barrier with their parents on the other side which leaves no one working on the fields. Since the children are in danger of starvation, Edilio sends Quinn to San Francisco De Sales island to get Albert back. Albert, regretting his escape decides to go back to Perdido Beach and once again feed the children.