Episode: (401) The Beginning of the End
Why it’s important: The fourth season is set up, and we are introduced to the idea of the Oceanic Six.
Unanswered questions: How can Hurley and Lenny see Charlie at Santa Rosa? Who’s eye does Hurley see in Jacob’s Cabin with Christian?
Episode: (402) Confirmed Dead
Why it’s important: We meet Charlotte, Miles, and Frank for the first time and get a glimpse of their past through flashbacks.
Unanswered questions: How can Miles talk to dead people? Why were the Dharma polar bear remains in Tunisia? Why was Frank replaced as the pilot of Oceanic 815?
Episode: (403) The Economist
Why it’s important: We learn that Sayid works for Ben off the island, and Daniel finds out that the island does something weird to time.
Unanswered questions: Why do Naomi and Elsa have similar bracelets? Who is the Economist?
Episode: (409) The Shape of Things to Come
Why it’s important: Ben timetravels and when the Barracks are attacked by the freighters, Alex is one of the casualties.
Unanswered questions: Did Claire become an island ghost like Christian after the house she was in blew up? What are the rules that Ben and Widmore discuss at the end of this episode and who put them in place?
Episode: (411) Cabin Fever
Why it’s important: We learn about important times in Locke’s past, and we find out that Locke has to move the island.
Unanswered questions: To whom did the objects that Ricard Alpert showed the young John Locke belong?
Episode: (412/413) There’s No Place Like Home
Why it’s important: We see the arrival of the Oceanic Six, and the freighter blow up, the island move, and we find out who was in the coffin.
Unanswered questions: Who built the frozen donkey wheel? Why did Ben say that whoever turned it could not return to the island?