The Flame Bearer (The Saxon Stories, #10) by Bernard Cornwell

Britain is at an uneasy peace. After their bloody defeat of Danish-held East Anglia, the West Saxons stand victorious while the Mercians have taken back their land on the border of Northumbria, the last kingdom of Britain still ruled by the pagan northmen. A precarious truce exists between Æthelflæd’s Mercia and Northumbria, now ruled by Uhtred of Bebbanburg’s son-in-law, Sigtryggr.

Under the cover of this fragile calm, Uhtred must begin his campaign that will end with the assault on Bebbanburg, the great fortress that is rightly his and was stolen from him in childhood. But his plans are shattered when the Scots surge down and lay claim to the north of England, as the West Saxons, under Uhtred’s old enemy, Æthelhelm, invade Northumbria from the south. If Uhtred is to succeed in recapturing Bebbanburg he must both defeat Æthelhelm’s forces and drive the Scots away before he can attack the formidable fortress by the sea. He has a small army and many enemies, but Uhtred is not the supreme warlord of Britain for nothing...