Not much is know about her past and parents and the extinction of the people of Laputa, but when she was young, her parents were killed by Muska's army and she was forced to live with her grandmother in Gondoa. Before her parents died they gave her an powerful jewel known as the Aetherium Crystal. Her grandmother taught her spells to protect herself, but years later her grandmother died and Sheeta was now an orphan, however she was given the house. At 12, she took care of herself and her farm until Muska and his men kidnapped her for their purposes of finding Laputa castle.
Upon an airship heading there, she was in a crossfire between Muska and a pirate gang led by an old woman named, Dola who also wanted Sheeta for they was told that there was treasure in Laputa castle. Sheeta escaped by going out the airship, but she lost her footing and fell off. Free Falling unconsciously, her Crystal activated and she ended up safely falling which caught the attention of a boy named Pazu. Pazu saved her and brought her to his house.
When she woke up, she saw Pazu and thanked him, upon exploring his house she found a picture of Laputa castle, Pazu told her that his father found that place, and people didn't believe him as they called him a liar which ended up in his father's death for explainable reasons. Pazu said that he will prove to people that Laputa was no lie. Men from Dola's gang arrived at Pazu's house looking for her, but they quickly left and was on the train tracks. They soon got in another crossfire with them and Muska's army. Pazu fell off the tracks with Sheeta and the Crystal saved them as they floated down deep in the mines. While in the mines, Sheeta told Pazu her story about her home.
When they escaped the mines Sheeta trusted him enough to reveal the truth about her and Laputa to him. But before he could learn more, they were captured by Muska and his army. Upon his army's headquarters, Muska explains that he knows the truth about Laputa even her real name. Muska made Sheeta a deal that if she cooperated he will keep Pazu alive and set him free. She agreed with the deal to protect him. Upon captivation, she remembered a protection spell from her grandmother unknowingly activating a robot from within the headquarters. The robot protected her until it's destruction. While falling the robot unknowingly snapped off her necklace and the Crystal fell. She was saved again by Pazu and Dola and her gang who took Pazu because he wanted to save her.
Wanting to find the truth they stayed with Dola and her gang on their airship. While on there Sheeta told Pazu a spell from the Crystal known as the spell of destruction. Upon reaching clouds that looked like a tornado that kept circling, they got flanked by Muska and his army Pazu and Sheeta got away on a glider reaching Laputa first.
Upon looking inside the castle they saw Muska and his army with the captured Dola gang. Pursuing Muska, they got spotted. As Pazu was hanging on for dear life on a pillar, Sheeta got captured again and was taken to the war room where all of Laputa's weaponry was being controlled, Muska also explained to Sheeta that he's also a Laputian and someone who was also part of another royalty line. He used the Crystal Sheeta dropped to show Laputa's power, killing his own army that he turned against. Sheeta reclaimed the Crystal and ran from Muska with him following her from behind. Sheeta found Pazu who survived and gave the Crystal to him. Muska soon had enough and was now willing to kill Sheeta with a gun as they ended up in the throne room. Sheeta explained that he will never rule Laputa, and both her pigtails were shot off by Muska. Pazu arrives back and was willing to give the Crystal back to Muska if he would only let him speak to Sheeta. Muska agrees to one minute. Pazu runs to Sheeta with the crystal in hand and asked for the spell of destruction. When the minute was up, Muska asked Pazu where the Crystal was, only to know that he and Sheeta had it said a word that would destroy the destructional part of Laputa. Muska was blinded by the spell and got killed within escaping the castle. When the tree from Laputa which was also bound to the castle was free, they returned to their glider which wasn't destroyed and flew away to reunite with Dola and the gang.
Upon saying goodbye to the Dola gang, Pazu and Sheeta flown off to Possibly Sheeta's home in Gondoa. It's unknown if they stayed there or went back to Pazu's house after, but throughout it they still were together.