In Tangled, months into her pregnancy, Arianna becomes gravely ill. A desperate search for a miracle cure is put into order, and over time, the royal guards locate and retrieve a magic, golden flower with the ability to heal the sick and injured. The flower is broken down and consumed by Arianna, who successfully recovers from her illness. A healthy baby is born, named Rapunzel, and to celebrate her birth, Arianna and Frederic release lanterns into the sky. One night, however, Rapunzel is kidnapped by a wicked woman named Gothel, who selfishly wants the healing power of the flower (now in Rapunzel's golden hair) for her own. By the time Arianna and Frederic notice her intrusion, they are too late. A search party is sent out, by Rapunzel remains lost. Arianna and Frederic release lanterns into the sky each year on Rapunzel's birthday in hopes that she will someday return.
Eighteen years later, the festival has become more of a memorial as Arianna and Frederic once again prepare to release thousands of lanterns into the night sky. Moments before the event, Frederic weeps silently at the thought of his lost daughter, Arianna softly comforts him before heading out into the balcony. Unbeknown to either Arianna or Frederic, Rapunzel is alive and within the kingdom, having escaped the tower in which Gothel has held her prisoner. After she returns home, she is still unaware of her origins, but her experiences in the kingdom refresh her memory, making her realize she is the "Lost Princess" of Corona. She confronts Gothel, and with the help of her lover and former thief, Flynn Rider, manages to escape her clutches and returns to the kingdom. While on their down time, Arianna and Frederic are notified of Rapunzel's arrival by a guard, and they rush to greet her. Neither immediately recognize her (with her hair having been cut and turned completely brown), but upon further inspection, Arianna realizes her daughter has returned and warmly embraces. Frederic follows suit in rejoicing, and Flynn is pulled in by a grateful Arianna shortly afterward.
During the epilogue, Flynn explains that Corona spent an entire week rejoicing over Rapunzel's return. Like Arianna and Frederic before her, Rapunzel became a beloved and giving ruler, with a familial relationship with her parents as strong as could be.
Arianna and Frederic return in Tangled Ever After. On the day of Rapunzel and Eugene's marriage, they are both present. Frederic walks Rapunzel down the aisle, while In Maximus' dream sequence after he loses the rings, Arianna exclaims from the audience that the rings were her grandmother's. They also appear at the end, giving Maximus and Pascal a surprised look that they were both dirty and messy, and also smiling happily as their daughter is married.