The mood and tone of "The Cay" over the first five chapters is quite serious. The book is taking place during World War Two, which is not exactly a wonderful and lighthearted piece of history. The setting is a Dutch colony island off the coast of Venezuela, and right away a German U-boat shows up. This obviously makes the people on the island edgy and nervous. Most of the islands supplies come by way of cargo ship, so the presence of German submarines means that tankers will have a hard time getting in there without being torpedoed. And that's exactly what happens. So the people are low on supplies like fresh water and resupply ships are being sunk. That's bleak. The main character, Phillip, and his mother try to escape the island by taking another ship out. It gets torpedoed, Phillip is knocked unconscious, and wakes up in small raft with a strange man. Phillip is in and out of consciousness, doesn't know where his mother is, doesn't know the guy he is with, there aren't supplies, he's seasick, and no sign or rescue. For Phillip, the main mood of the first five chapters is fear and hopelessness.