Loosha was born in Misthallery'sGolden Garden. When her parents died, she was the last of her kind left, and suffered from loneliness. This made her leave the garden for the upper level of the lake, where she found Arianna and Tony. She made friends with them, and kept the siblings company after the death of their father.
In the year following up to Last Specter, Descole's machines destroyed various parts of the town in order to find the Golden Garden. Loosha tried to fight them off, which caused the two of them to look like the specter destroying buildings. To calm Loosha down, Arianna played her ocarina into the town's old irrigation pipes, echoing through the town and calming Loosha.
When Professor Layton, Luke and Emmy confronted Arianna and Tony, Arianna played the flute to summon Loosha. Minutes afterwards, Levin Jakes and his police officers captured Loosha and arrested Arianna, taking them to the town square.
After Descole revealed as a true behind for tearing apart of Misthallery. Loosha once again fought the machine with the help of Layton, Luke, and Emmy. Loosha, realising how to stop the machine, broke down the secondary floodgates of Misthallery's dam, lightly flooding the town and short-circuiting the machine.
Once the battle had ended, Loosha used the last of her strength to break through the primary floodgates of the dam, badly flooding Misthallery, but revealing a hidden passageway to the Golden Garden. When they finally reached the garden, Loosha collapsed, and died from her wounds, sacrificing her life to save Arianna's, as her illness could be cured by the pure air in the garden. Before she died, Loosha said "Thank you" to Arianna and Tony, as translated by Luke, causing Arianna to become very emotional. Her body was carried away by the current in the water to the bottom of the lake. Arianna played her ocarina one last time in Loosha's memory.
Some time later, the town erected a statue of Loosha in front of the dam in honor of her sacrifice.
A huge, lovable aquatic creature displaying remarkable intelligence, Loosha is the last survivor of the Golden Garden. She fought bravely against the mechanical specter to protect the town and her two best friends, Arianna and Tony.