Obviously, as I carve up the finale of this fourth season of “Top Chef,” spoilers will be forthcoming. Please don’t read further if you still want to be surprised — although, seriously, if you were a real fan, wouldn’t you already have watched?

Although there were three people in last season’s finale, I still expect the equivalent of a quick fire in which one of this year’s remaining three — Stephanie, Richard and the dreaded Lisa — will be eliminated. Wrong. They barely get a glass of breakfast juice at their gorgeous hotel in Puerto Rico (El Convento, “begun as a Carmelite convent 356 years ago”) before they’re plunged into the challenge that will determine the winner. Three famous chefs (including “culinary god” Eric Ripert of Le Bernardin) will serve as their sous chefs as they prepare a four-course tasting menu including (eek!) dessert. Nobody much wants to make dessert. They get three hours to prep and four hours the next day to finish; everybody but the supremely confident Lisa seems shaky. It’s amusing to see Stephanie hover over Ripert — culinary god, remember?

I’m easily impressed by knife skills, but the prep phase is a bit of a bore, except when Richard, the advocate of molecular gastronomy, pulls out his liquid nitrogen to make Tabasco ice cream and the famous chefs gather around to watch it work. Oddly, Lisa (who gets along with no one, as Stephanie points out) is getting along well with her chef, April Bloomfield of the Spotted Pig gastropub (I got that off Google) in New York. Richard has Dan Barber, a New York chef who’s all about fresh, local ingredients. (Again, Google.) They chop and prep and refrigerate, and I have never seen so many plastic containers in my life. Could a major maker of plastic containers possibly be a sponsor? Hmmm.

Next day, the twist is that the sous chefs won’t be helping, so the three are on their own. Richard has his nitrogen out again, this time to make bacon ice cream. (Yum!) But he’s not serving the Tabasco variety he tested before. Stephanie is making what she sometimes calls a ricotta pound cake and once a cheesecake, which seems like a bad sign. Lisa is going on about how she’s going to be the first female Top Chef. They are very quiet, and somehow they finish.

The famous chefs judge along with Padma, Tom, Gail, Ted Allen and Mr. Zagat from the Zagat guides, plus a noted Puerto Rican chef. The three serve their courses head to head, all at once. Lisa has spicy grilled prawns; Richard does almost-raw scallops; and Stephanie serves grilled red snapper, all with lots of accessories. The diners seem to like Stephanie’s dish the best. “Almost really good,” Tom says.

At this point, I pause to wonder why we enjoy a show in which we watch other people taste great food.

Richard cooks a complicated thing with guinea hen, foie gras, an egg and the kitchen sink for the second course. Lisa does a coconut soup with a dumpling; they love it. Stephanie has quail breast over lobster ravioli. Tom hates the leeks, which he finds undercooked; also, they have “no relevance,” Gail complains.

Consensus is that Stephanie’s lamb — with pistachios, blackberries and olive tapenade — is the winner in the third course. Lisa’s wildly expensive Wagyu beef is tough, and the sauce is too sweet; Richard’s pork belly is flabby fat after being pressure cooked and strikes me as gross.

Lisa’s dessert course, a black Thai rice pudding, is so complicated I can’t even describe it. Richard makes a banana scallop (he’s done that before) with bacon ice cream. (How can they like that? And yet they do.) Stephanie’s cake is “OK but nothing special” according to the Zagat guy. It actually looks delicious to me, with banana cream and fruit on it.

“Really they’ve all won at this point,” Gail says — and yet, they haven’t. But “there were some missteps along the way, some serious and some small,” Tom says. Called before the panel, Stephanie says she thinks she second-guessed herself on the dessert but can learn from it. Ms. Ego, Lisa, envisions the panel saying, “She deserves to be Top Chef.” Richard says, “I think I choked.”

So the judges debate — and, apparently, debate and debate and debate. I’d have liked to be a fly on the wall (or a Bravo producer) for that, although I’d have wanted to go to bed long before dawn, when they’re apparently still debating as the birds start to sing. They like Lisa’s dishes so much that it’s a little nervewracking.  A viewer poll at the last, long break finds 60 percent for Stephanie, 36 percent for Richard and a whopping 4 percent for Lisa.

But time’s running out, and they have to make room at the end for a plug for the new season of “Flipping Out,” so Padma doesn’t dilly-dally with the announcement: “Stephanie (six seconds) you are Top Chef.” “Really?” she responds. Hugs and champagne all around.

One final thought — the prize for this agonizingly torturous competition is just $100,000. You’d think the “Glad family of products” could come up with a little more cash, considering how much product placement they get. Oh, and where do I buy trash bags with a huge, red “Glad” on them? Gotta have those.

Another final thought: girl power!

And a final final thought: There’s a reunion special next Wednesday.