Designing plastic-bottle cars to put to the test on an obstacle course. But can over-engineering stop the cars getting around the track? A simple re-engineer could solve the problem so the cars are fit for purpose.

Bob wants to plant a sign on the top of Mount Robo-Bob, so they set off in grippy shoes to climb it. They meet Ranger Bevel, who tells them about the abominable snow monsters and says he'll guide them up the mountain safely. At the summit, Bob plants his sign, but then the snow monsters appear, causing Ranger Bevel to slip and slide down the mountain uncontrollably. Bitz sees Bob's sign and they all leap on it to give chase, but they can't stop and they overtake Bevel.

Bitz, Bob and Bevel are racing across the desert in a steam train to deliver ice cream for the opening of Purl's ice cream parlour. But rustlers Zippy the Kid and Prospector Pop want to get their paws on it and create a distraction before making off with the train's engine. Our heroes manage to get it back but there's no water left in the tank, which means there's no steam to make it go - and the ice cream is starting to melt in the heat.

When Ranger Bevel gets stuck in a pile of soft snow on High Snowy Mountain, Bitz needs to work out how they can pull him out without sinking into it too!

Princess Purl has lost her tiara and it turns out it's been taken by two naughty castle trolls who parade around showing it off high up in the castle. Bevel pole vaults over the wall to get it back, but he looks straight into the trolls' special goggles and is frozen into a statue. Then Purl rushes in and is frozen as well, and so is Bob.

Bitz and Bob are on the lookout for spaceships in the Big Hot Sandy Desert when a rocket crash-lands near them. They rush off to help and meet two aliens who speak a very strange language. They call them Plipp and Zopp and manage to discover that they need to get back to space in time for granny alien's birthday.