It is now becoming increasingly clear that Desmond is the wild card in the island. The Others may know everything about the survivors of Flight 815, but they clearly had no idea about Desmond's existence. They didn't know about his boat, and when Juliet was getting set up in the final scene of the previous episode, she looked at Desmond without any hint of recognition at all. Because of this, there's an excellent chance that he will be the savior of those on the island. The first time this becomes possible occurs here in 'Catch-22' Once again his flashes are telling him that Charlie's life hangs in the balance, but this time, if he doesn't let fate carry through, there's a good chance that the other part of his vision won't come true--- and this time, the vision involves rescue from Penelope.
Each flashback in Desmond's past seems to be happening before the previous one, and this one has another huge shock --- he was a monk, which also explains why he calls everybody 'brother'. Furthermore, before he became a man of the cloth, he was engaged to a woman named Ruth. He left her at the altar because he believed he had a higher calling, but as always the women who love Desmond see through his facade. She tells him" next time you want to break up with someone... just tell the girl you're too bloody scared." (Unfortunately, he won't learn his lesson, will break up with Penelope for the exact same reason, and hear almost the exact same line from her.) The interesting thing comes after he breaks his vow of silence to talk with Ruth, and then proceeds to get liquored up (Desmond seems to get more drunk than anyone else on the island) He is then fired by Brother Campbell who tells him that he has some kind of destiny before him, but God isn't part of it. (Which leads us to wonder is someone else leading Des on? In the last flashback, we can see that there is a photo of Ms. Hawking, a.k.a. the ring lady from 'Flashes Before Your Eyes'. Is it possible that he is somehow leading him down this path.) Before the flashbacks ends, we also see Campbell last act was to inadvertently introduce Desmond to Penny, who is buying wine for her father.
Now that he's on the island, Desmond is no longer running. He tried to get away from his destiny before--- he ran when he thought the hatch was going to explode, got onto a boat and tried to escape--- but he couldn't get away. But now Desmond is trying to move forward, now that he sees another of his flashes, and this one seems to lead to Penelope.
We know that Penelope has been searching for the island, and now Desmond seems to get proof. But in order for his vision to become a reality, he needs Jin, Hurley and Charlie to take him on a journey. While they are out camping, they see lights in the sky, and what appears to be a helicopter, and soon evidence that someone parachuted out, and that person may well be Penny. But in order for this to work, Charlie needs to run into one of Rousseau's traps, and he has to take an arrow to the neck.
Once again, however, his basic goodness gets in his way, and he saves Charlie. But as soon he does, he thinks he has changed destiny, and that now Penny won't be there--- which would seem to be borne out by the fact that Penny is not the woman in the plane. But if you watch the flash carefully, you can see that Charlie and Jin were there while Desmond cut the woman down, meaning he had to be there in order to save her. Was the flash giving him conflicting information? Or did fate change so that Penny wasn't there? We will later see that Penny was nearby, but is it possible that she really would have saved them then?
Meanwhile, on the beach, things are returning to normal, sort of. The triangle of Jack, Kate and Sawyer has be reformed, only now, it's become a square with the coming of Juliet. Kate is glad to have Jack back, but now he's been distant and unfamiliar, and seems to favor Juliet instead of her. This leads to another shift which ends up putting Kate willingly in Sawyer's arms. He's got a catch-22 of his own in that he loves Kate, but she still seems to be carrying a torch for Jack. however, those feelings are what drive her to Sawyer's bed. However, in typical Sawyer fashion, he doesn't seem to mind that he's being used as long as he gets what he wants. He can live with this--- for now.
Whichever side of the Jack-Kate-Sawyer triangle you come down upon--- and I was one who didn't hold much care for either--- Desmond's love for Penny may be far more vital. Was this woman sent by Penelope? We will later learn that she wasn't. Then why did she have a photograph of Desmond with her? Why was Desmond the first word out of her mouth? We will later learn a lot about this woman--- and it will be very difficult determining how much of what she said was true. The episodes centered around Desmond's are easily becoming the most eagerly awaited of the bunch, not just because Cusick is such a fine actor or because the love story is taking on the appearance of epic proportion, but because unlike most of the people on this island, Desmond seems to be the most eager to go. He wasn't on the plane, but it's becoming clear his destiny his ensnared with those of the passengers on it. The question is, will this destiny eventually be true for everybody?