6 1 20 Space Plague Harrison, Zac Additional Author mixed material 9781434279354 Minnesota Stone Arch Books 2013 Hyperspace_High_Space_Plague.jpg.jpg Frozen Enemies Harrison, Zac Additional Author mixed material 9781434263117 Minnesota Stone Arch Books 2013 Hyperspace_High_Frozen_Enemies.jpg.jpg Crash Landing Harrison, Zac Additional Author mixed material 9781434263100 Minnesota Stone Arch Books 2013 Hyperspace_High_Crash_Landing.jpg.jpg Warlord's Revenge Harrison, Zac Additional Author mixed material 9781434263131 Minnesota Stone Arch Books 2013 Hyperspace_High_Warlord%27s_Revenge.jpg.jpg Robot Warriors Harrison, Zac Additional Author mixed material 9781434263124 Minnesota Stone Arch Books 2013 Hyperspace_High_Robot_Warriors.jpg.jpg Galactic Battle Harrison, Zac Additional Author mixed material 9781434279347 Minnesota Stone Arch Books 2014 Hyperspace_High_Galactic_Battle.jpg.jpg