Complex sentence: On the first night, Naruto uses a clone as a decoy to escape from prison, but his clone is secretly taken by Mui to have the Nine-tailed beast's chakra extracted which leads him to learn about Naruto's escape plan.
Split into simpler sentences: On the first night, Naruto uses a clone as a decoy to escape from prison. During his escape, his clone is secretly taken by Mui to have the Nine-tailed beast's chakra extracted which leads him to learn about Naruto's escape plan.