S1·E18 No Need for a Ghost

Sasami is visited one night by a mysterious young girl named Mirei, who invites her back to her own ship to play. Mirei can create wonderful illusions with the wave of her hand, and she and Sasami have fun together in places from each others' memories. Meanwhile, the others, sick with worry over Sasami's disappearance, board Mirei's ship to search for her, but find the vessel has been deserted for hundreds of years.