"Things go from bad to worse on the island. Elsewhere, Walker decides to go to St. Germain after learning about Brother Michael."
The immortal, Brother Michael is trying to breed other immortals by impregnating successive generations of his daughters/granddaughters in the hope that eventually his immortal genes will accumulate to the point of surpassing whatever human genes are left in his offspring. At the same time he wants to stop humans from breeding. So he has created an apple that causes people who eat it to become sterile. But even though the apples are otherwise safe to eat, honey made from their pollen causes people to become the freaky violent plague victims. And now, for no apparent reason, Michael decides to kill all of his non afflicted followers. I don't understand why, what does that gain him? I could understand if he was going to kill the sick ones, but why kill his healthy followers that provide all his labor on the island?
Meanwhile Julia learns about Michael and his island and plans to go there. But we already know that she apparently doesn't get there for another thirty years. Wonder what holds her up that long? About all I can think is somebody makes her a prisoner.