Shaun, a mischievous sheep living on Mossy Bottom Farm, grows tired of the daily routine and devises a plan to take a day off. He tricks the Farmer into falling asleep, but things quickly spiral out of control when the Farmer is accidentally sent away to the Big City in a caravan. The farm falls into chaos without the Farmer, prompting Shaun, his flock, and their loyal dog Bitzer to venture into the unfamiliar urban environment to rescue him. Their journey is complicated by an overzealous animal control officer who is determined to capture any stray animal he encounters.

The flock navigates through a series of comedic misadventures in the city while trying to locate their Farmer. They disguise themselves as humans, narrowly avoid capture, and make new allies along the way. Shaun and his friends must race against time to bring the Farmer back before the farm descends further into disarray, learning important lessons about friendship and resourcefulness. As the story unfolds, the devotion and cleverness of Shaun and his companions shine through.