Penny and Desmond have a son they call Charlie. Maybe Desmond does feel guilt for getting Charlie killed to be reunited with Penny. Desmond likes to tell Charlie about the "very special island" of Great Britain while Penny thinks they should tell him about Grandfather Widmore who "sent a boat to kill all daddy's friends." While running around Oxford, Desmond learns that Daniel did something to a woman that left her comatose and that Widmore was involved.
Meanwhile Locke, Sawyer, Juliet, Miles, Daniel and Charlotte are in 1954 and discover that the US army were on the island then, planting tripwires, landmines and a hydrogen bomb. Daniel acts very suspiciously and Juliet reveals that she's been holding out. Juliet reavels that the Others speak Latin and that she knows something about Richard. Neither Juliet or Locke are that surprised to see that Richard is in charge of the 1954 Others. What Locke is surprised about is that Charles Widmore is one of the Others.
Now this was good. So where is the hydrogen bomb now? Was the sickness Danielle was on about in season 1 actually radiation poisoning? Richard seemed to be the leader, yet spoke about answering to someone. Does he answer to Jacob? Why doesn't he age? What did Daniel do to Theresa? How did Widmore get off the island and build his empire? Who are the Others? Who or what is Richard?
Anyway Locke creates Richard's interest in him as seen in season 4's 'Cabin Fever' and this ep explains where the US army knife seen in season 2's 'The Other 48 Days' came from. The Others seem to have little that is truly original or indigenous to them, their genius is synthesis.
"Richard's always been here."
"How old is he?"