A old kindly Podling, she found Kira when she was just a child, after the latter lost her mother. The Podling took her in, raising the Gelfling as her own daughter.
When Kira returns to the village, Ydra is shocked and delighted to see Jen as she, and the rest of the world, had assumed only one Gelfling had survived. Ydra excitedly welcomed Jen into the village and made him sit as the guest of honor at the Podlings' celebration. Ydra dragged a bashful Jen onto the dance floor; with Ydra's guidance Jen quickly loosens up and joins in the Podling dance, joining in with his Firca.
When the Garthim attack the Podling village, Ydra is captured and tossed into their cages to be taken to the castle. Jen sees Ydra screaming for help in the cages of the Garthim when the Gelflings and Landstriders battle outside the castle. He attempts to free her, but is unsuccessful.
When in the castle Kira encounters the captive Ydra only to find that her foster mother's essence has been drained; the once cheerful and merry Podling that she loved had become nothing but an expressionless slave. Kira is saddened and shocked, but once the Crystal is healed and the urSkeks rejoined, the Podling slaves, including Ydra, are freed and return to their regular selves again.
- Although more is told about Ydra in the novelization, Her name is spoken once in the movie, but it takes a sharp ear to catch it. When Ydra approaches Jen and Kira's table during the party, she says, "Jen, viselitye?" And immediately afterward, Kira laughingly retorts, "Ydra!!" This implies that she might have said something inappropriate or suggestive about Jen and Kira's potential relationship, which may have embarrassed Kira, even if Jen didn't understand what was said.
- Ydra is named and described in detail in the film's novelization, The Tale of the Dark Crystal, and The World of the Dark Crystal.