Toby's dad and little sister have been kidnapped by pirates, and Toby is left alone in the aftermath of the terrible Red Fever epidemic that has wiped out much of the world's population. Menacing tribes of super-intelligent dogs are gaining ever more ground in Scotland and moving northward. A mysterious figure called The General is leading a group of villains who are kidnapping people and imprisoning them in a place he calls New Caledonia. But where is this New Caledonia, and what does The General plan to do with his captives? – Toby sets out on a perilous mission to find New Caledonia and, he hopes, his family. He befriends a Russian girl, whose family has also been taken. Together they sail to Inverness and down the Caledonian Canal, trudging through the snowy Highlands until they reach Stirling Castle and the dramatic final showdown. In a freezing cold winter and with vicious dogs, wolves, and pirates on the rampage, will they make it in time? – Black Tide is the dramatic sequel to Red Fever, which won the Kelpies Prize in 2010.