When Alfie and Ava find a strange box of mechanical parts at the back of the shed in Alfie's new house, they make an amazing discovery: when they put all the bits together, they make a robot. Even more amazing, it works!They soon discover that this robot is called B4 - and he claims to be able to take people to any point in history. That's how Alfie and Ava travel 150 million years back in time to a world crammed with dinosaurs - some of them distinctly unfriendly!

When Alfie and Ava find a strange box of mechanical parts at the back of the shed in Alfie's new house, they make an amazing discovery: when they put all the bits together, they make a robot. Even more amazing, it works!They soon discover that this robot is called B4 - and he claims to be able to take people to any point in history. That's how Alfie and Ava travel 150 million years back in time to a world crammed with dinosaurs - some of them distinctly unfriendly!