That car is the Chevy Volt, GM's plug-in electric sedan. It remains a concept car; in fact, the only hum it emits at the moment is coming from GM's PR machine. When it was introduced with great fanfare last January, skeptics asked: Is GM serious, or is this just a PR stunt? But even though GM still hasn't set an official production date, its TV campaign for the Volt is one more sign that this time, the company is putting its reputation on the line. Now, the question is simpler: Can GM deliver?

The Volt is a plug-in electric sedan driven exclusively by lithium ion batteries, though it also incorporates an onboard "range extender" -- normally a gasoline engine, but in principle using anything from diesel to a hydrogen fuel cell -- to recharge them while driving. According to the terms of a new contract with the United Auto Workers union, GM has assigned a Michigan plant to produce the Volt, starting in 2010 -- which GM executive have cited as the company's "internal deadline" for getting the car into production.

The big hitch, however, is the batteries: so far, they don't exist and there's no certainty that they'll work as they must to make the Volt viable. That's an unusually frail premise for a national ad campaign. Why would the No. 1 car maker in America -- and until recently, in the world -- take such a radical and risky step?

The short answer: GM doesn't want to get Priused again.

The longer answer is that the auto industry is in for a jolt that will make the oil shocks of the 1970s feel like a Jacuzzi. GM knows it. Larry Burns, vice president for planning and R&D at GM, believes failure to adapt would be GM's death knell.

"It's critically important to replace petroleum-based fuels and diversify our energy supply," says Burns. To succeed, GM must say goodbye to the gas-powered engines that have fueled the company's profits from the very beginning. "There has been tremendous growth in the auto industry worldwide," he notes. "GM can't have its business growth capped by energy, safety, or environmental issues. We need a transition from the internal combustion engine — a technology that has been essentially the same for 120 years."

Hence GM's new tagline: "From gas-friendly to gas-free." The Volt is Exhibit A in GM's campaign to tell the world that tagline is more than hot air -- as well as being the car maker's best chance of competing with Toyota for green mindshare. With Ford and Chrysler on the ropes -- and companies like Tesla getting ready for prime time -- it also may be the last hope for the old-school American auto industry.

The good news for the industry is that GM seems to have seen the light, and is determined to seize the day.

When the Volt was unveiled at the Detroit Auto Show in January 2007, the buzz was instantaneous. Car buffs and journalists couldn't get enough of the aggressively styled concept car with its in-your-face electrical charge cord. Toyota was blindsided by the announcement, according to auto industry insiders. The Japanese company reportedly yanked several oversized, gas-guzzling trucks off the show floor to avoid unflattering comparisons -- and damage to its carefully reconstructed brand. If GM was hoping to cause a stir, its wish came true.

But the excitement was tempered by skepticism. After all, wasn't it GM that killed the electric car -- specifically, the EV1, one of the fastest, most efficient production cars ever built? It was, in fact, GM's announcement of a radical EV prototype that had inspired California's Zero Emissions Mandate (ZEV), itself one of the most radical anti-pollution laws in U.S. history. The ZEV, enacted in 1990, required that 2 percent of new vehicles sold in California be emission-free by 1998, and 10 percent by 2003.

According to GM's critics, the company made the EV1 available to consumers only to comply with California law, and only until it could get the law changed. In fact, GM refused to sell the vehicle, leasing it instead while retaining ownership. Once the zero emissions mandate had been gutted, GM went back to business as usual, while the EV1 -- despite drivers' protests -- went into the compactor.

So after pulling the plug on a zero-emissons vehicle that ran on pure electricity and put American automotive technology in the vanguard worldwide, does General Motors really expect to blunt Toyota's charge with a concept car whose battery packs still don't exist? Yes, GM's EV resurrection was unquestionably a coup. But was it for real?

Bob Lutz says Yes. Lutz, GM's vice chairman for product development, is a car guy's car guy, with an unapologetic passion for power and speed and a deep belief in bold design. Lutz is known for bringing style back to GM -- and if the General does manage to get his groove back, Lutz will deserve a lot of the credit.

As an old-school Detroit car guy, Lutz is clearly galled by Toyota's ascent -- especially since he sees the Prius "halo" as hypocritical, given Toyota's predilection for churning out high-margin, gas-guzzling trucks.

"Unfortunately, when it comes to fuel economy," says Lutz, "the Prius has shed its environmental image on the whole Toyota product line. I ask people why they bought a Sequoia instead of a Tahoe, and they say, 'It's the fuel economy.' I say, 'You realize the Sequoia gets 17 miles per gallon and the Tahoe gets 21.'

"Somehow they can't deal with that," he adds, "because they know Toyota makes the Prius, whereas we are the producers of the Antichrist called the Hummer H2. The vehicle that creates our image is the Hummer H2; the vehicle that creates the Toyota halo is the Prius."