A tiny, one-eyed shell named Marcel lives a unique existence with his grandmother Connie and their pet lint, Alan. They reside in a sprawling American home once bustling with the life of a large family of shells. After a mysterious tragedy, the shell community has been whittled down to just Marcel, Connie, and Alan. Despite his diminutive size, Marcel's boundless optimism and creativity enable him to turn everyday household objects into thrilling adventures. With bottle caps as skis and tennis balls as vehicles, he crafts a rich life filled with exploration and wonder.

When a documentary filmmaker discovers Marcel while renting a room in the house, he becomes fascinated by the shell's quirky and endearing ways. The filmmaker begins to record Marcel's daily activities, broadcasting the footage to a rapidly growing online audience. As Marcel's story gains popularity, his infectious spirit and heartfelt outlook on life touch the hearts of viewers. This newfound attention sparks hope in Marcel, leading him to dream of reuniting with his long-lost shell family. With the power of the internet at his disposal, Marcel begins a quest to find his relatives, all the while navigating the vast and sometimes perilous human-sized world around him.