The first season of "The L Word" ends this weekend. It has been an increasingly self-assured run, in which virtually every character has been explained, explored and redefined.

The episode is steamy, even by this show's standards. And the sex scenes, as throughout the season, are charged with many different types of emotion.

Yet, such scenes are anything but gratuitous.

Take, for example, Jenny (Mia Kirshner). Fourteen episodes ago, when "The L Word" premiered on Showtime, she was a beautiful young suburban naif, happily engaged to Tim (Eric Mabius) and only passingly curious about the lesbian couple next door. A few visits and secret encounters later, and one of the couple's friends, the smoldering Marina (Karina Lombard), had seduced the smitten Jenny.

As the season played out, it appeared that Marina was a sexual predator who delighted in first-time conquests. Jenny returned to Tim, and married him, but her sexual confusion continued. They separated, and Jenny eventually found herself sexually drawn to Robin (Anne Ramsay), a researcher, and then to Gene (Tygh Runyan), a young marine biologist whose office includes a glass-lined wall of the aquarium where he works.

It is against that glass - against the seals and other marine life swimming on the other side - that Jenny decides to confront her conflicting urges by attacking him aggressively. He presses her up against the glass, and the two begin having frenzied sex - until she begins to sob. He stops, she cries, then collapses, exhausted and even more confused.

It's a very hot scene, one of many in Sunday's finale (10 p.m.), but it's driven totally by character and a season's worth of development.

Series creator Ilene Chaiken, who wrote the finale, gives every cast member challenging material to close out the season.

And director Tony Goldwyn, with this particular scene between Jenny and Gene, gave his actors the ultimate responsibility. The entire scene, from the first impulsive approach to the final emotional meltdown, is filmed in one long, unbroken camera shot. It makes it all seem that much more real, powerful and voyeuristic.

Other highly charged scenes include confrontations between Shane (Katherine Moennig) and Cherie (Rosanna Arquette), whose relationship threatened to turn into an all-female version of "The Graduate." Also, Tina (Laurel Holloman) finds out about the growing passion between Bette (Jennifer Beals) and Candace (Ion Overman).

No character is remotely the same as when the season began. Relationships are reworked or destroyed, and surprises are served up at several points along the way.

As the word gets out about how good "The L Word" is, expect the parade of noteworthy guest stars, like the involving and evolving story lines, to only grow next season. This show has earned its praise, and its renewal.