The Staircase, Abducted In Plain Sight, Captive. All powerful Netflix true-crime docuseries. But have you heard about the Thanksgiving cheesecake conspiracy?

Philadelphia teamed up with creative ad agency GUT to launch a mystery of the ages.

In a bid to bring cheesecake back to the holiday shopping list, the infamous brand embarked on an investigation with the "Cheesecakers Society" (not a real thing, unfortunately -- we’ve already Googled) to unearth a centuries-old cover-up.

Karen, president and founder of The Cheesecakers Society."It has been a long journey, but the truth always finds a way. With our documentary, the world will finally know and for that we are thankful, for everyone who believed in us and for Philadelphia who supported our cause."

The mini-documentary follows the journey of Karen as she investigates clues and real historical paintings by Karen Rinaldo, Jean Gerome Ferris, and Jennie Augusta Brownscombe, piecing together the evidence that leads her to an unimaginable discovery: Cheesecake was indeed served at the first Thanksgiving.

The Cheesecakers Society reached out to both the Pumpkin Pie and Pecan Pie societies to get a statement regarding their involvement in the cover-up of this historical event and connections with lobbyist groups trying to keep the discovery under wraps, but they declined to comment.

Megan Magnuson, associate director of marketing for Philadelphia, said: "At first we were hesitant about the theory. But once we saw the evidence and the original paintings it was clear to us. Cheesecake is 100 percent the original Thanksgiving dessert. We think…

"We fully support the honorable Cheesecakers Society in their quest to restore cheesecake to its rightful place at the Thanksgiving table."

The short documentary film is supported by a campaign in social, digital, billboards and print ads, all exposing the evidence found by the Cheesecakers Society, and will be running a week before Thanksgiving to give the public a chance to embrace the truth in their celebrations.