Each of the characters in The Tempest finds themselves in bondage. However, by the end of the story, the same characters are set free from whatever enslaves them. A few characters one can see enslaved are Prospero, Miranda, Ariel, and Caliban.
Prospero is in bondage to his magic. Since his exile by his brother from his dukedom in Milan, he has had but a few books to help pass the twelve long years. During this time, he becomes very proficient in the magic, and often uses magic instead of dealing with people normally. His liberation comes when he gets his dukedom back from his brother and decides to give up magic with the help of the audience's "good hands" (V.i.9) to set him free.
Miranda is in bondage to her innocence. She has known no other men than Prospero and Caliban, and she has never known any women, so she does not know any of the dating conventions.
All she can do is dictate her heart to Ferdinand without artifice. Her liberation comes as her father gives his consent for her to marry Ferdinand. Ferdinand has had experience with women so he will be able to teach her the conventions of the time.
Ariel is in bondage to Prospero, who saved the spirit when Sycorax stuck him in a pine tree. Ariel has to play tricks and use magic in accordance with Prospero's wishes. It is apparent that Ariel wants his freedom very much. The spirit's liberation comes at the end of the play. After Ariel has served his year of servitude to Prospero, Prospero sets him free.
Caliban is in bondage to Prospero's magic, but mostly to his monstrous looks. Prospero uses him as a slave because Caliban looks sub-human. Since Caliban is actually not human, he does not have the demeanor of them. Others try to civilize him to be a noble savage, but he belongs to nature as seen through the attempted rape of Miranda. Sadly, liberation cannot happen with Caliban because his looks are immutable.
Although the action in the play is simple, the meaning behind the characters is important to recognize. Without recognizing the theme of bondage and liberation, the characters are flat and uninviting. The liberation of the characters at the end of the play ties in with the fact that the play is a comedy. The happiness of liberation fits very nicely with the happiness of promise of marriage and forgiveness to come.