Although pushed into retirement by old age, Grandfather and his constant canine companion Roo quickly find themselves thrust back into action onboard the ominously named Unsinkable, in search of the mythical King Cod. Written as a series of short letters to his gender-neutral grandchild and as the Unsinkable’s ship log, Grandfather again finds himself suffering from a bout of bad luck compounded by Roo and her finicky ways, which seem to change with the wind. It isn’t long before the Unsinkable gives the lie to its name and the adventurers find themselves in the titular bind. Black-and-white illustrations are sprinkled throughout, with short quirky annotations from Grandfather that add even more humor and depth to this zany adventure. Packed with silly hijinks and fantastical creatures, this last of the Lasts (The Last Cowboys, 2008, etc.), with its endearing duo of grandfather and Roo, delivers fun for readers new to chapter books. (Fiction. 6-8)