▁offset ▁pressure ▁differences ▁between ▁plan ets . ▁ ▁They ▁land ▁safely ▁on ▁Metal una , ▁but ▁the ▁planet ▁is ▁under ▁attack ▁by ▁Z agon ▁star ships ▁gu iding ▁met e ors ▁as ▁weapons ▁against ▁them . ▁The ▁def ensive ▁" ion ization ▁layer " ▁is ▁failing , ▁and ▁the ▁battle ▁is ▁entering ▁its ▁final ▁stage . ▁Metal una ' s ▁leader , ▁the ▁Mon itor , ▁reve als ▁that ▁the ▁Metal un ans ▁intend ▁to ▁fle e ▁to ▁Earth , ▁then ▁ins ists ▁that ▁Me ach am ▁and ▁Adams ▁be ▁subject ed ▁to ▁a ▁Th ought ▁Trans ference ▁Chamber ▁in ▁order ▁to ▁sub j ug ate ▁their ▁free ▁will , ▁which ▁he ▁indicates ▁will ▁be ▁the ▁fate ▁of ▁the ▁rest ▁of ▁human ity ▁as ▁well ▁upon ▁Metal un an ▁re location . ▁Ex eter ▁bel ieves ▁that ▁this ▁is ▁imm oral ▁and ▁mis gu ided . ▁ ▁Before ▁the ▁couple ▁can ▁be ▁sent ▁into ▁the ▁brain - re programming ▁device , ▁Ex eter ▁helps ▁them ▁escape . ▁Ex eter ▁is ▁badly ▁injured ▁by ▁a ▁Mut ant ▁while ▁he , ▁Cal ▁and ▁Ruth ▁fle e ▁from ▁Metal una ▁in ▁the ▁sau cer , ▁while ▁the ▁planet ' s ▁ion ization ▁layer ▁becomes ▁totally ▁in effect ive . ▁Under ▁the ▁Z agon ▁bomb ard ment , ▁Metal una ▁he ats ▁up ▁and ▁turns ▁into ▁a ▁lif eless ▁" radio active ▁sun ". ▁The ▁Mut ant ▁has ▁also ▁board ed ▁the ▁sau cer ▁and ▁attacks ▁Ruth , ▁but ▁dies ▁as ▁a ▁result ▁of ▁pressure ▁differences ▁on