After Desmond turned the failsafe key, he saw a series of flashes, and then relived a day of his life in 1996. Back on the island, he met Hurley in the jungle. He told him that Locke made a speech about rescuing Jack, Kate, and Sawyer. Hurley says he does not know about the speech. Later that day, Locke said the speech as Desmond had said.

Desmond tries to move Claire away from her tent, but she declines to. Desmond then builds a makeshift lightning rod out of bamboo, wires from the fusalage and a golf club by her tent. Hurley asks what it is, and Desmond says it's an experiment. A minute later, it starts raining, and lightning hits the rod. Later, while having a conversation, Desmond act strangely. Suddenly, he starts running, and swims into the ocean, where it turns out Claire is drowning. Desmond saves her, and Charlie and Hurley wonder how he knew she was drowning, and ask Desmond how he knew. At first, he did not say, but later that night, he says that he had flashes of this, and that during both the events, he was not saving Claire, but saving Charlie. It is then when he says that it is Charlie's destiny to die .

Claire comes up with an idea that could get them saved. She spots some migrating birds, and says if they capture one, they can attach a note to it, and a scientist observing the migration patterns could find the note. Desmond finds a gull by some rocks, and captures it. He later says that if he did not catch the bird, Charlie would of, but would slip and fall into the ocean, and slam into the rocks.

Another day, Desmond, Charlie, Jin and Hurley are walking through the jungle when it starts to rain. Charlie steps on a booby trap (most likely made by Rousseau). An arrow hits him, and he dies. Then there are a series of flashes; Hurley lifts the cable on the beach, the helicopter over the ocean, the picture of Desmond and Penny, Jin, Hurley, and Charlie holding the parachute, the parachutist, and Penny on the Island. All of this was a flash of Desmond, but when the time actually happens, Desmond saves Charlie, but the future is altered, and Penny does not end up on the Island.

In another premonition of Charlie dieing, Desmond sees Charlie in the Looking Glass. there is a flashing yellow light. He flips the switch, and then drowns, but then another flash is of Claire and Aaron getting on a helicopter. He says to Charlie that he must die in order to save them. When Charlie went inside the Looking Glass, there are two girls, Bonnie and Greta, who capture and interrogate him. There is a flashing yellow light, but no switch as Desmond said. Instead there was a code that needed to be entered. Desmond and Mikhail later appeared in the Looking Glass. Mikhail killed both Bonnie and Greta, before Desmond shot him with a harpoon. Charlie managed to get the code and entered it. Suddenly Penny appeared on the monitor, also not mentioned by Desmond. Mikhail appears at the porthole, with a grenade, and breaks the window, flooding the room. Charlie shut the door before this happened. It is unknown if he will survive or not.

Questions:

• How did turning the failsafe key cause him to have premonitions and relive part of his life.
• Why are his premonitions centered around Charlie dying?
• Will Charlie die?

Yes, Charlie will die. He will appear to Hurley while Hurley is in the institution when he is back home because Hurley has gone nuts again.

After the episode, "The Constant", we learn more about the nature of Desmond's time traveling abilities. Desmond is having constant flashbacks and they are getting worse until Daniel tells him to find "a constant." Desmond does that, with Penny, and the connection between the two will keep Desmond alive. Just like Desmond is going to keep Daniel alive. I believe that Desmond will arrive back at the island with Daniel.