'Vigilance is Vital' when you're a Pack Protector. That's why Ruff and Tumble are always alert and on the lookout for Invaders. Well, Ruff is anyway. Having just saved the Pack Lands from a Horde of Goblins, Ruff now uncovers a new threat. Dog Eating Yetis have frozen the world and are ready to invade. Can Ruff save the Pack Lands? And can he get Tumble to help? This is the second book in the Ruff and Tumble series. Each book can be read independently, with no need to have read the previous books in the series. This book has illustrations and some fancy/exaggerated fonts to engage younger readers. It has been written as a self reader for advanced younger readers or as a story book to be shared by parents with their primary school aged children (and has proved to be as popular with the adult readers as the children). Ruff (Rufus) is a Scottish Terrier. He is black and shaggy and gets overly excited. He is also a little nervy. He has far too much imagination for his own good and reads books which only fire him up more. He tends to get a bit confused between real life and his dreams. Tumble (Thumbelina) is a Pembrokeshire Corgi. She describes the breed as, 'an ancient, Welsh, wolf like breed, not overly tall, used for herding cattle, very graceful and beautiful.' She thinks quite a lot of herself but is willing to get her paws dirty to do what is right. She acts like Ruff's older sister. In fact Ruff and Tumble are very much like brother and sister: they tease each other, play tricks and banter a lot, but ultimately they look out for each other.