The Rise and Fall of the Grumpy Burger follows filmmaker Marshall Sfalcin as he attempts to create a movie about his family's former fast-food empire. By day, he works as a construction worker in Windsor, Ontario, and by night, he makes films. His latest project involves chronicling the rise and fall of the Hi Ho Restaurants, founded by his grandfather Amie Fortin. Marshall's uncles, initially supportive, begin to resist as he delves into the darker aspects of their family history. With his project unravelling, Marshall finds solace in visits with his grandmother. Filmmaker Matt Gallagher documents this journey, blurring the line between truth and fiction.