Beanotown is in trouble again and this time the threat is Jurassic! The Mayor is determined to capture some of the pre-historic inhabitants of Duck Island for display in the zoo and will stop at nothing to get his way. Together, Dennis and Gnasher set out to thwart the Mayor’s horrible plan and save the day. Minnie, on hearing the news that an island of dinosaurs is situated so close to home, sees an opportunity that can not be missed.

She wants a pet and what could be more awesome than a raptor? Upon arrival it soon becomes clear that no-one’s plans are going the way they expect. Enraged, the Mayor decides to wreck the alien do-hicky thingy-ma-bob that stops the island expanding. Now the whole town is in trouble.

Strange meat-eating plants flop through the streets, there’s dinosaurs in the supermarket, swimming pool and cinema, and raptors are riding the subway. The only way to get things back to ‘normal’ is to put the do-hicky thingy-ma-bob back together. But for that, they’ll need Gran’s help.