Martha's Grandad Gilbert comes to visit, but has forgotten how to have fun, so Grandpa sets out to remind him.
Grandpa tries to fix one of Mr Mentor's inventions but struggles to get inside the machine.
Mr Mentor the Inventor has devised bicycle bells that Mr Liker Biker wants to try out at Dad's bike shop, but Grandpa needs to find a way to make him leave.
Jason's aunt wants to cook his mother's freshly grown vegetables, but Grandpa disapproves of the idea.
When Floyd has a little accident in the garden, Grandpa suspects he is just pretending to be hurt. He wants to catch Floyd out, but needs to find a way to prompt him to run.
Jemima looks forward to playing with a new friend, but when he arrives he is too shy to join in. Luckily, Grandpa and Jason are on hand to help the boy learn to have fun.
Jason and Jemima are putting on a Captain Dumbletwit play. All is going well until Floyd turns up and takes over. Disaster then strikes, but Grandpa is determined that the show must go on.
A new girl at school comes round to play with Jemima but wants everything her own way, so Grandpa decides to teach her a lesson.
Bubbles the babysitter has a new kitten which she brings round to show to the Mason family. Unfortunately Floyd turns up and tries to make Bubbles jump. Before long Floyd gets a taste of his own medicine.
Jason visits the toy shop to choose a birthday present for his friend Dora, but Grandpa cannot resist shrinking and coming along too.
Grandpa helps out at the bike shop while Mr Liker Biker struggles to deal with a very important customer.
Jason and his cousin make a model caveman, but it gets damaged - so Grandpa steps in to save the day.
Jason and Jemima join a club to learn how to cook some of Miss Smiley's recipes, but Floyd wants to join to cause mischief.
Alvin becomes obsessed with trying to beat the Masons at games including table football, leaving Grandpa worried by his over-competitive nature.
Jason and Jemima visit a toyshop with Grandpa.
Mr Mentor invents something to pick up litter after Mr Whoops hurts his back cleaning up rubbish on the beach.
Mum makes fancy-dress costumes, but things get out of hand when Mrs Maridadi comes to help.
Mr Whoops buys a music box for Miss Smiley, but has an accident with the key, and Grandpa is forced to don his cap to save the day.
Great Aunt Loretta has trouble looking after a friend's goat.
Bubbles the babysitter teaches everyone how to flamenco dance, but Great Aunt Loretta tries to take over.
Great Aunt Loretta makes a clock for a competition in which she could win a holiday.
Mr Whoops wants a dog, but Mum challenges him to first look after Wulfy for the day.
Mum invites a cruise ship captain to stay when his vessel breaks down in Sunnysands, but when he begins to boss everyone around, Grandpa comes up with a scheme to get rid of him.
Great-aunt Loretta plans an invention, but Grandpa gets in trouble when he wants to become involved.