If you haven’t watched “Lost” before, you are missing out on television’s most audacious and exciting shows.

It’s one of the most ambitious shows on television, as it aspires to be entertainment that succeeds on several different levels: as straight up sci-fi, drama, romance and action.

Best of all, it provokes heated discussions, and it’s highly interactive, with easter eggs hidden throughout the show.
“Lost” could have easily remained a show about plane crash survivors living on a deserted island, but the character flashbacks throughout the past four seasons allow the characters to become fully realized rather than just archetypes (the pretty girl, the heroic doctor, the tortured musician, et cetera).

Luckily, the writers can do more or less whatever they want because they don’t need to worry about alienating other viewers, since all those still watching are the ones who are truly invested in the show.

Thank goodness for that, because “Lost” has upped the stakes this season. With the series set to end in 2010, the writers clearly know the end game, and intend to make it a wild ride.

“Lost” takes major risks this season by revealing how six of the original plane crash survivors were rescued and adding the extra element of time travel on the island.

Apparently the island moves through time, wreaking havoc and major headaches for those who never left the island.

Both the mythology of the island (The smoke monster! The four-toed statue!) and the characters are richer too, as the time line of the show changes with every episode.

The characters we have come to love and hate continue to grow as we learn more about their past and present. Ben (Michael Emerson), the mysterious leader of the Others, wants everyone to go back to the Island.   But it’s fascinating to watch how far he’ll go this time to get what he wants. After all, a man who lets his daughter get killed by a mercenary is infinitely more complicated and fascinating than any character on “Gossip Girl.”

Few shows have plotlines or arcs shaped around female characters. “Lost” has an abundance of them. The ongoing mystery of why women can’t give birth on the island is tied to Juliet, a former Other. Kate’s interactions with Jack and Sawyer, the main love triangle in the show, help to enrich the layers of both men who couldn’t be more different –– Jack the heroic doctor and Sawyer the ex-con man.

With a diverse cast, including three Asian characters and one Iraqi, “Lost” is one of the richest ensemble dramas on TV.

With a show like “Lost”, which aspires to be a billion different things, the strength of the show ultimately lies in its layers.
You can watch the show on many different levels: as a sci-fi show to see how they could possibly explain what is going on with all that time/space continuum warping, or as a character study about Jack and Locke’s daddy issues, or even just to find out how they’re going to explain away all the island’s mythology that included polar bears and a smoke monster.

There are plenty of reasons to watch “Lost.” So prepare to embrace your inner sci-fi geek and your inner romantic, and catch up on the past four seasons of   “Lost,”   Wednesdays at 9 p.m.