Last week, Jim Cramer was blown away by one company that delivered a fantastic quarter, thanks to the low price of crude. In fact, Carnival is in such a sweet spot right now that Cramer decided to find out what the secret for success has been for the stock.

Carnival is the world's largest cruise line play, and because cruise ships are such gas guzzlers it has been reaping major benefits from the low cost of oil.

"It is not just that one of the company's largest costs has fallen through the floor, Carnival has also been the beneficiary of a magnificent turnaround," the "Mad Money" host said.

It was just 14 months ago when Wall Street pretty much considered this stock to be road kill after a series of high profile disasters. But while most investors were obsessing about these disasters, Carnival was already at work turning itself around, thanks to the leadership of CEO Don Arnold.

Arnold took over in June 2013 and aggressively cut costs, streamlined the company's many disparate brands to improve efficiency and managed to repair its reputation.

With so much work done by Arnold to rejuvenate Carnival, Cramer was totally blown away when it reported such a tremendous quarter last week.

Carnival's cruise and tour costs declined by 11.2 percent year-over-year, mainly because fuel costs were down by more than 45 percent in the same period. At the same time, Carnival was able to effectively raise prices.

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"Costs going down, prices going up — that is the Holy Grail of running a business," Cramer said.

Clearly, there is a lot going right with Carnival right now. But with the stock closing at $54 on Wednesday, up from $50 last Thursday, does this mean investors would be chasing the stock if they purchased Carnival at these levels?

Cramer does not think so. In fact, he would be a buyer. While these low oil prices cannot last forever, Cramer believes they will be lower for a long time. That is a huge positive for Carnival's bottom line.

And what really boggles Cramer's mind is that the stock is selling for just 16 times next year's earnings estimates. That is simply too cheap, in Cramer's opinion, for a company that is putting out such stellar results.

"When your costs are going down but you can raise prices on your customers, that is nirvana for business people. Right now, Carnival is in precisely that situation; I think it is a buy," Cramer said.

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