Mr Mentor's new invention, the Wonderbubble Weather Watcher, says that it's the perfect weather for a boat trip, but Grandpa's not so sure. He shrinks so that he can go sailing with Elsie, Bob and Mr Mentor. As Grandpa suspected, the invention isn't working properly and once the party gets out to sea they realise that a storm is brewing.

Mr Mentor panics and knocks Bob over, hurting his arm. Then Mr Mentor manages to break the boat's engine so they can't get back to Sunnysands. They seem doomed! Luckily, Grandpa is small so he can get inside the engine and fix it. Show less