Flashes Before Your Eyes

Desmond sees the future. Since he turned the failsafe key, he knows what's coming. Charlie will die. He saves him once. Then again. But death always comes back.

Flashback. Or rather: time travel. Desmond wakes up in his London apartment. With Penny. Everything starts over. He remembers it all. The island. The hatch. The button. He can change things. He's going to buy the ring.

A woman in the jewelry shop. Eloise Hawking. She knows. She refuses to sell him the ring. "The universe has a course correction mechanism. You cannot change the course of events." Desmond puts the ring back. He loses Penny. Again. Destiny isn't a straight line. It's a loop.