Theresa Breslin 
Dream Master Nightmare 

When Cy visits a special Viking exhibition in York and looks at a glorious Viking helmet, he is horrified to suddenly find a face in the helmet – his Dream Master! The Dream Master is in terrible trouble, a prisoner of Eric Bloodaxe – a fearsome Viking chief. Only Cy can rescue him. But first he must enter his dreams again . . .
This is the second terrific adventure involving Cy and the Dream Master and is just as packed with action and wit as the first title.