What is the theme of inkdeath?

Inkheart is about Mortimer Falchart and his daughter Meggie, who were left alone after Mortimer accidentally read some characters out of, and his wife (Theresa/Resa) into a very special book - Inkheart. The story is about Meggie discovering all of this and the characters trying to capture Mortimer and his magic voice, as well as all the copies of their story; while Mortimer is trying to find his wife again.