The Secret of Linden Hall is the first of the Timberley Three series and in this adventure the three Timberley children meet Professor Linden and his cook Hettie for the first time. There is confusion and skulduggery. A misplaced book and some steel hedgehogs. Is the Professor mad and will Billy's ingenuity and bravery save them all?

When Slugina, a strong willed, self opinionated and fearless explorer comes to stay in the Deep Wood, upset and mayhem follow. Her Uncle Limpy (a snail), Hopple the rabbit, Dumpy the mole, and Brentonwood the dwarf have their lives turned upside down by her mischievous antics. But when Sparkles the dragonfly goes missing it is Slugina's strong character that helps her overcome her own fear and earn the respect of her Uncle and his companions. Although, Slugina being Slugina, she makes sure that she has the last laugh.