Carnival (CCL 2.34%) (CUK 2.18%) navigated stormy seas in the earliest days of the pandemic. The world's biggest cruise company was forced to halt sailings, and that resulted in profit plunging and debt swelling to record levels.

However, once Carnival's ships returned to the seas, the company did all it could to supercharge recovery, from focusing on fuel efficiency to spurring more onboard spending by guests -- and the efforts worked. Since then, Carnival has made great progress on its plan to reduce debt and return to profitability.

But has that been reflected in the share price? Let's see how much you would have today if you'd invested $10,000 in Carnival four years ago.

Two people on a cruise ship deck point to something in the distance.

Image source: Getty Images.

A stock in the doldrums

If you'd invested that amount in Carnival in April 2020, a time when the shares were in the doldrums, your investment would be worth $12,600 today. That might not seem like a tremendous gain, but it's a good start, considering the difficult economy in recent times.

Last year's high-interest-rate environment made investors reticent about betting on companies with high debt levels or that depended on consumer spending. Carnival falls into both categories.

But there's reason to be optimistic about the cruise company over the long term. It has made progress paying down its debt, even prioritizing the payment of variable-rate borrowings, and has reported record demand for its cruises and steady steps toward profitability. In the most recent quarter, booking volume and revenue reached records and the adjusted net loss came in narrower than the company expected.

What does this mean for investors? Carnival makes a great recovery story stock to hold onto for the long term.

The company is advancing steadily toward its goals of becoming profitable and lowering debt, and solid demand for its cruises -- even through tough economic times -- is encouraging. All of this means you could have a lot more to gain by hanging on to Carnival shares as the positive momentum continues.