I’m a world class kayaker. I live in the San Diego area, where I can use my kayak all year long. I need to make some money and I find, to my surprise and delight, that I can make money with my little kayak. I hire on with a research outfit for a bit of south seas adventure. It seems that many small south seas islands are surrounded by a barrier reef. Sometimes the only way in or out to an island is via a small gap in the barrier reef and then only at high tide.
The people that I’m working for have found a few such islands. They want to obtain some materials and observations from some of the barrier reef protected islands. The only practical way in and out is my kayak and that only at high tide.
I join the expedition, my kayak and I board the research ship and off we go, headed for the south seas.
The scientific people aboard our ship have some sonar equipment that finds a narrow path through the barrier reef of the first island that we come to.
I go in, over the barrier reef of the first island, gather a few samples from the island and do some observation, as per the directions of the expedition scientists. (I’m not a scientist, I don’t really understand what I’m to do, I just do what I’m told.) When I finish my assigned work, I have nothing to do, so I kind of wander around the island for a while. I then come back out over the barrier reef some twelve hours later when the tide is again high enough to allow me passage back out. I deliver the materials and observations to the scientists and earn my pay.
The second island looks to be more of the same thing as the first island. I go in over the barrier reef and land on a very narrow, rocky beach. The whole island looks to be basically one gigantic rock. Even the beach is just a few rocks broken off the giant rock and smoothed a bit by a million or so years of tide and wind. I gather a few rock samples, as directed, and then try to find a way up the cliff that seems to go all the way around the island. There’s a way up the cliff, steep but barely manageable. When I get to the top of the rock I find a sort of shallow bowl. There’s a structure in a sheltered place near the rim of the bowl. There’s not supposed to be a structure, as the island is supposedly uninhabited and uninhabitable. It’s a puzzle.