Complex sentence: The arc begins when the Mei fruit of Qing Qiu, which may give wondrous powers to the being who eats it, is stolen, with Fei Yue as the only witness.
Split into simpler sentences: The arc begins when the Mei fruit of Qing Qiu, which may give wondrous powers to the being who eats it. It is stolen, with Fei Yue as the only witness.