What do you look like if you time travel? Perhaps like a lunk-headed Austrian, naked and with fizzy blue stuff all over you. Or perhaps, to the confusion of Professor Travers, you look exactly as you did when he met you in Tibet forty years ago. That escapade has had a legacy, as he has brought back a deactivated robot Yeti – and has mistakenly managed to reactivate it. Or perhaps, you look very much like yourself if you're a time traveller, for just by reading this book you won't change your appearance, but you'll be sent back to 1968, by way of 1975, when this book-of-the-series was first published.