Grandmaster Glitch is visiting London and spots the perfect souvenir at a riverside stall - a majestic hat that was clearly made for a Grandmaster! But when he finds he has no money, he decides to raise some by working as a tour guide on the River Thames. \n\nThe Go Jetters are also visiting London while Lars helps to fix his favourite his bridge - Tower Bridge. Ubercorn explains that this amazing bridge can be raised to allow tall river traffic to pass safely beneath. While Lars goes to fix Tower Bridge, Xuli, Kyan and Foz jump onto a riverboat tour, unaware that they are in fact boarding Grim HQ! Before they can jump ship, Glitch sets sail, giving out his very own glitchy 'facts' and spending his customers' money on his Union Jack hat. But when the hat blows away in the breeze and Glitch gives chase, he puts tourists, boats and Tower Bridge itself in danger.