• by Sarah Mahoney , Staff Writer @mahoney_sarah, Yesterday

It’s hard not to love “The Last Square,” General Mills’ new effort for Cinnamon Toast Crunch. The campaign is designed to appeal in equal parts to true crime fans, mascot lovers and sugary cereal consumers. After debuting a campy video last week, General Mills is adding even more mystery, inviting consumers to help uncover “The Last Square” to win a year’s supply of Cinnamon Toast Crunch.

The Minneapolis-based company is setting the search up as playfully as possible, sending boxes of cereals to food influencers, each containing just a single square, seeding creators’ imaginations with reports of muffled crunching from behind pantry doors and swirls of loose Cinnadust. “After launching an internal search, we traced the source to a limited run where some Cinna-Squares seem to have snacked their way through the rest of the box,” the company says in the announcement.

“Look, we’re surprised but not sure the cereal is really to blame here,” says Brandon Tyrrell, senior marketing communications manager at General Mills, in the campaign announcement. “Still, this bizarre (but undeniably delicious) development has forced us to act. We’re running out of time — and cereal — and we need your help.”

The cereal killer campaign is already a hit on social media but comes as the company caps a tough year. General Mills just announced fourth-quarter results, including a 7% drop in North American retail sales. Net sales dropped double digits for the U.S. Snacks operating unit, and mid-single digits for U.S. Morning Foods, including cereals.

“Top-line growth continues to elude General Mills, as the packaged foods sector struggles given a strained consumer,” writes Kristoffer Inton, an analyst who follows the company for Morningstar, noting that the company anticipates that next year, organic sales will gain 1% at most, and may even decline 1%.

The company is looking at several ways to recapture volume growth, including price investments, narrowing the gap between branded and private labels, new packaging options, and stepped-up ad spending for new products.

General Mills is also diving into the fresh pet food category, currently dominated by Freshpet, with a fresh food offer from its Blue Buffalo brand. And Edgard & Cooper, a leading European premium pet food brand General Mills bought last year, will debut in the U.S. this July through an exclusive retail partnership with PetSmart.

While it will take some years for General Mills’ pet food profits to catch up with others in the category, says Inton, “we see management's actions as prudent and likely to help restore growth.”