It was forbidden to enter the tower.

The law had been handed down from a time beyond man's memory, and none who broke it had ever survived.

From the tower flowed the energy and intelligence that kept alive the city of Noi Lantis, the sole vestige of civilization left on Earth.

The Earthling, Kymri, and the beautiful invader-girl, Mirlana, already had violated a great and terrible taboo by daring to fall in love. 

Now they were about to commit the most fearful transgression of all.

But there was no turning back as they slid open the glittering tower doors. Within was the secret that could spell man's last hope for survival - or his final sentence of doom....