Sixamians, as highly sexualized society, have developed technologies of using sexual acts between sex partners and their arousal as a main source of energy - so-called p-factor. Their dark ages were merely the prolonged series of wars for sex slaves. Over centuries they became more civilized and in the scientific era developed consensual and non-exploitative ways of obtaining p-factor, but the essence - sexual act - remained unchanged. Now, alone on the alien planet, they had to find ways to replenish their p-factor reserves.