Is a thriller book by Elizabeth Kostova.

The novel tells the story of a young girl who is looking for her father who mysteriously disappear. Before he disappear her father began to tell her a story about his years in college, and after he disappear she found the continuation of the story in letters from her father directed to her. The story was about both, her father and mother, looking for the historical Vlad the Impaler,Dracula, in a search that took them to Romania, Hungary, Bulgaria and Turkey.
At the end of the book she finds her father and mother,who found and killed Dracula.

the thing that you don’t have when you’re phones percentage is over 20