It is a very entertaining play, with only three acts, so if you haven't already, I highly recommend reading it. For a brief summary however, I have provided a link below, and that should help.
One of the main themes in the play is the theme of progression versus tradition, represented in the two main male characters, the progressive schoolteacher Lakunle, and the traditional tribal chief Bale "The Lion". Throughout the entire play they combat ideals and beliefs, all in the ruse of winning Sidi's love. Sidi herself is encapsulated by this theme, representing many of the Nigerian people's indecision between tradition and modernism. She sees value in them both, and it is hard for her to commit to one view over another; many of the Nigerians of the time period were caught in this trap, not sure which world to live in.
For more details on characters and plot, take a look at the links below, and good luck!