Twins Scarlett and Thomas are studying the Vikings and Anglo-Saxons at school, and have a homework project to do - so Grandad comes to the rescue with his time machine. Thomas is catapulted onto a Viking longship, and it's not long before he's being told tales, fitted out with armour and weapons, and getting ready to fight the Saxons. But, uh-oh, his sister Scarlett has landed in a Saxon village: in a pile of pig poo, to be exact. Things seems to be getting better when she befriends the young Alfred the Great - but watch out, Scarlett, there's a Viking ship on its way . . .