Lost season 5 begins......

The season 5 premier of Lost brilliantly introduced time travel as a major component of the storytelling. The people left behind on the Island are randomly jumping through time. There’s a mystery about whether the points in time they jump to is random or pre-ordained, but other rules have been established.

Dr. Marvin Candle and Daniel Faraday both explained that people can’t change the past, and that any attempts to do so will fail. However, Faraday also revealed that, for unknown reasons, Desmond is special and immune from this rule.