|Beaver paperback (Hamlyn imprint), 1977. Cover illustration|
by John Raynes.
Rear cover synopsis:
"The mysterious powers of the zero stone on his rung bring danger to young Murdo Jern. Together with his strange feline companion Eet, he is hounded through space by the murderous Thieves' Guild, helped only by Eet's super-human intelligence and the unpredictable stone itself."