Adapted from Forrest Wilson's books, the children's programme revolves around a grandmother with super powers and her arch nemesis, The Scunner Campbell.
While watching her grandson play football, Granny Smith (Gudrun Ure) is hit by a ray created by Inventor Black (Bill Shine), giving her magical powers
Inventor Black is warmly invited to exhibit his latest invention, the Skimmer, at the prestigious Modern Times exhibition in Chisleton, so, Supergran takes it for a test run. Once The Scunner Campbell gets wind of the new all purpose vehicle, he steals it and presents it to his former cell-mate Roly Roofless. Together they plan to use it as the ultimate getaway vehicle in a silver bouillon caper.
Eccentric Scotish millionaire Angus McSporran comes to Chisleton to ask Supergran for his hand in marriage. Simultaniously, the Scunner Campbell is also the Black Pudding Heiress Lady Valerie Glutt. Supergran doesn't like the thought of either of these romantic pairings.
The Scunner plans to grab the fabled Pearl of Pinnels End right from under the chin of Mrs. Digby Day by using Inventor Black's latest, greatest invention: the Invisible Shield.
The Chisleton Athletics are facing off against the unbeatable Mighty Rovers and even with the encouragement of Supergran, it seems like the hometown boys stand no chance at all. The Scunner Campbell is also betting on the Chisleton team, because he owes Vincent Eleven pounds by Saturday.
The honorable Bertrand Battenburg visits Chisleton and Mad Mick of Merseyside is out to replace him with a mechanical double (and kidnap the original copy). Unfortunately, Supergran, who is supposed to protect the Battenburg boy, gets hits on the head with a log thrown by Geoff Capes and loses her superpowers. Meanwhile, the Scunner plans to get his hands on the honorable Bertie himself in order to rise up from the bottom position on the Top 50 criminals league.
Supergran comes to the aid of The Great Renaldo (birth name: Ronald MacDonald) and his mother Clinging Ivey. Once a great magician, Renaldo lost his confidence after being tricked out of his act (and applause) by Fabulous O'Finnigan. Supergran proposes to use Inventor Black's new Manual Hypnotizer machine on Renaldo. Meanwhile, wanting to thwart the Tartan Tornado at every turn, The Scunner invites Fabulous O'Finnigan to Renaldo's comeback show.
While Supergran is taking driving lessons, the rest of Chisleton is excited about the arrival of film company Convix Pix. Little do they know that mega producer Vince van Perfect is merely the Scunner Campbell in disguise and planning to rob the Big Ben Clockshop.
Glaswegian master of disguise Greta Garboils teams with the Scunner and dresses up like Supergran (with the Muscles posing as Willie & Edison) to commit crimes. Soon the real Supergran is arrested and put on bread and water in the Chisleton police station.
Supergran and Willie are enjoying a day out in Paddleton upon Sea. However the Scunner and his accomplices are also there, trying to get their hands on the widow Groggelbank's dog.
Chisleton has got marathon fever. Even the Scunner and his cronies are practicing, but only so they can rob the Chisleton bank on race day.
When Supergran organizes a Chisleton Beauty Contest, the Scunner is tasked by the head of the Gangster Guild to make sure her daughter Wanda ends up the winner.
The Scunner Campbell is chasing a winning lottery ticket lost by a gust of wind. Mrs. Petunia Preston is missing Cyril the Snake (actually an old vacuum cleaner hose) and now can't perform at the Orphan's Tea Party.
