Ghosts of Illyria

The Enterprise visits Hetemit IX, an abandoned colony of Illyrians, a people barred from the Federation for practising genetic modification. An ion storm strands Pike and Spock on the surface, while the returning landing party carries an illness that spreads through the ship, compelling the infected to seek light at any cost. Number One is unaffected, and as the crisis deepens she is forced to reveal that she is secretly Illyrian herself. Her modified biology provides the basis for a cure. On the planet, Pike and Spock learn the colonists tried to undo their modifications to join the Federation and were transformed into beings of plasma who now shelter the pair from the storm. Una offers to resign, but Pike refuses, though she is left unsure he truly accepts her. The infection slipped past an outdated transporter that M'Benga has secretly kept running: his terminally ill daughter Rukiya is stored in its pattern buffer.