Kaizoku Sentai Gokaiger

Luka sees a jewel she desperately wants, but to her displeasure a little girl buys it before she can get her hands on it. Suddenly, the girl's father approaches Luka. He'll give her the jewel if she comes and works in his house, and so she is invited. Within the house there seems to be a treasure, as the Zangyack are targeting it as well. For the sake of doing some recon, and protecting a potential treasure, and also for selfish reasons, Luka decides to take the job. But can Luka really do said job? And what is the treasure the Zangyack are looking for?