Daphne Garsington was seconded from the British Consulate to an archaeological dig of a 3000-year-old Surene tomb in the vicinity of Ur in Lower Mesopotamia in 1924. She was employed as an assistant clerk. She supported women rights and was developing feelings for Archie Ferrers.
Daphne was asked by Colonel Lifford to enter the tomb first as she was the smallest person on the team. There she was attacked by saline drones and became contaminated, which resulted in an unquenchable thirst for salty water and made her assault other humans.
Her human mind was still present inside her: she recognised Bertie's voice and helped him and, through him, River escape from the inner chamber where Prim was held. However, she was not able to contain her thirst and attacked Bertie, contaminating him too. This gave her enough strength to leave the tomb and contaminate Archie, her admirer.
Both of them were returned to their normal selves for a short time when River blew up the dam and flooded the valley with salt water. As the saline drones could not process so much water properly, the couple died trying to hold on to each other. (AUDIO: The Boundless Sea)