It was a case of advertising working too well.

That's why Priceline.com decided to knock off its spokesman of 14 years, William Shatner. In the latest spot from Butler Shine Stern & Partners, San Francisco, a bus teeters on a bridge. Mr. Shatner helps shepherd riders out of the back to safety but is unable to exit in time as the vehicle makes a fiery and spectacular crash into a ravine.

Priceline.com Chief Marketing Officer Brett Keller said that only Michael Jordan for Nike and Bill Cosby with Jell-O were in Mr. Shatner's league as iconic endorsers. Which is precisely why he had to be killed off.

"One of the challenges we face is that Bill is so awesome and so closely associated with Priceline that we needed to grab back consumers' attention," Mr. Keller said.

The problem was that Mr. Shatner is so closely identified with his character, The Negotiator, and Priceline is moving to focus on its fixed-price discount (at 200,000 hotels in 140 countries) instead of the name-your-own-price business Mr. Shatner made famous.

"Bill is the face of name-your-own-price, and we felt we had to really get the message out about this," said Mr. Keller. "The published-price segment is the fastest-growing one for us."

But try telling that to Mr. Shatner. "No one was more shocked than I was," he told Ad Age in an interview. He learned about The Negotiator's demise in traditional Hollywood fashion: reading the script he was sent for the next commercial. "After they picked me up off the floor ... I saw what was happening," he said with a laugh.

Mr. Shatner made clear that he understood the business decision. "They wish to bring attention to the fact that Priceline does offer another service, this maximum discount without having to make a bid," he said. "That's the reason they're killing off the character -- to bring attention to another part of the business."

(Mr. Keller's version of the story is somewhat different: He said he personally reached out to Mr. Shatner to tell him he was receiving several new scripts from Butler Shine -- and "one in particular stands out in which we basically throw you off a cliff," Mr. Keller said he told Mr. Shatner. "He took it in great stride, and that 's the way he's been for 14 years.")

How he got the news might be in question, but one thing's clear: Mr. Shatner didn't get the bus -- er, boot -- because the campaign didn't resonate. According to an analysis by ABX comparing three recent Priceline ads with one spot each from Travelocity and Expedia, Priceline's averaged 20% better than its rivals. In fact, it came in almost 5% higher than the average for all TV ads in its index.

The only area where the Priceline ads trailed its competitors was in reputation. While the reputation scores were not low, they were not as strong as Travelocity's or Expedia's.

Mr. Keller also said the change to focusing ads on its fixed-price service was not precipitated by any shift in Priceline's financial health. In its most recent financial earnings report, for third quarter 2011, the Norwalk, Conn.-based company posted revenue of $1.5 billion, up 45% from the year-earlier quarter. Mr. Keller added that the new direction of the ad campaign was not a reaction to one-stop shopping offered by Kayak.com.

"Absolutely not," Mr. Keller said. "This is less about the aggregators and more about what we have to offer."

Between Priceline, Expedia.com, Travelocity.com, Orbitz.com, aggregator Kayak.com, and a new entry, RoomKey.com, online travel is a competitive, $109 billion-a-year business, according to PhoCusWright Research, which that predicts the industry will grow another 8% this year to $117 billion.

According to Kantar data, Priceline spent $31.5 million in measured media through the first 10 months of 2011. In the same period, Travelocity spent $50 million, Expedia $40.7 million, Kayak $28.6 million, and Orbitz $18.4 million.

Couldn't Priceline.com have just kept Mr. Shatner and put him in a new role for the fixed-price service? "You would think," Mr. Shatner said. "But they are so imbued with the passion of getting this message out that they thought the best way to do it was to bite the bullet. Or, in my case, biting the dust."

Ah, but this is the world of TV. Nobody is ever really dead, and Mr. Shatner actually remains under contract to Priceline. So will we see The Negotiator again? Depends on how the next phase of the campaign does without Mr. Shatner.

"I think, based on the ad, he has perished, but I think it's also fair to say that , based on how this current campaign moves forward, we'll make a decision on the direction we go," Mr. Keller said. "We're very much a results-driven company. The next phase of the campaign follows the aftermath that follows the demise. You will hear from the survivors of the crash talking about The Negotiator and what he has done for them, and some of their feelings about what he has taught them about our new products and services."