W5 cannot forget the experience of the light. She can't sleep, and finds herself replaying the vision over and over in her mind. Her sister worker and close friend X48 takes a leap and shares with W5 the location of her secret work space in a hollowed out tree root where she builds masks that perfectly mimic an ant's head. Going against every rule of the colony, W5 and X48 make a plan to sneak away and explore the surface.