Those Vikings

Karl McGregor is twelve years old and friendless. He has a temper, so the other kids at school steer clear. Friendship's tedious until a new student, Adam 'Finch' Bird, enrols. Finch confides that his dad's in gaol; Karl says his dad is from the ninth century. Of course, Finch doesn't believe him. This is the 21st century after all. Then a mysterious object appears in Karl's shed. The boys investigate.

They stumble across a dubious history professor, who tells them they've found the gamban ...