Guess who wrote the season's first weak episode?

They’re the four words that strike deep fear in any true ”Sopranos” fan’s heart: ”Teleplay by Michael Imperioli.”

Don’t get me wrong. The guy’s great as smack-addled wiseguy Christopher Moltisanti, but whenever creator David Chase allows the costar to pen one of the show’s scripts, it’s invariably the season’s weak spot.

I felt an even greater fear when I read the title of the Sept. 29 episode: ”Christopher.” Had Imperioli written himself a one-man show? No, it was worse. Much worse. He wrote an episode about… Christopher Freakin’ Columbus!

At the end of last week’s sensational installment, the feds had made Christopher’s fiancee, Adriana (Drea De Matteo), an offer she couldn’t refuse, while Tony (James Gandolfini) and Carmela (Edie Falco) didn’t know the whereabouts of daughter Meadow (Jamie-Lynn Sigler), who’d threatened to run off to Europe.

Did Imperioli’s script pick up where these cliffhangers left us dangling? No, instead we were subjected to an irrelevant, not-too-entertaining debate over whether Columbus was an Italian hero or a murderous racist.

The issue was framed by a storyline about Native American activists threatening to disrupt a Columbus Day Parade in Newark. That prospect got proud Italian-Americans like Silvio (Steven Van Zandt) and Ralphie (Joe Pantoliano) up in arms, bogging down the episode in ethnic politics. To make matters even worse, Imperioli felt the need to reopen the discussion of whether Italian-Americans are stereotyped as Mafiosi via a sequence about a professsor (the ironically-named Roma Maffia) who embarrassed Carmela by giving a lecture on the topic at a church luncheon. This fodder is better-suited to a ”New York Times” op-ed piece than a ”Sopranos” episode.

”Christopher” wasn’t a total time-waster, however. The show wisely continued to flesh out the character of Bobby Bacala (Steven R. Schirripa), Uncle Junior’s oversize assistant. His wife, Karen, was killed in a car accident, leaving the big guy bereft. Unlike his fellow goodfellas, he doesn’t even have a mistress to console him. At least his Family attempted to rally around him, as the wives took turns bringing him hot dishes — ”ziti patrol,” as Ralphie wittily dubbed it.

Janice (Aida Turturro) wasn’t able to provide a home-cooked meal — she picked up a bucket of KFC instead — because she was too busy violating Ralphie and berating him like he’s a ”hoo-wa” (as he pronounces it). Eventually, Janice?s shrink convinced her to break her vicious cycle of seeking her father/brother?s approval by dating equally violent men, and she dumped Ralphie — down a staircase. He threatened to kill her, setting up a potentially explosive showdown for next week’s episode. Unless, of course, the writers decide to drop this subplot along with the Adriana and Meadow storylines.

What did you think of ”Christopher”?