"Constant Subscriber" is a book written by Tessa Haig that tells the story of the mysterious disappearance of a young girl, Goi. The main character Catherine, who works in a local bookstore, finds Goya's diary and decides to go in search of the truth. The closer she gets to solving the mystery, the more she risks discovering an unexpected truth about her past and family. This book is an exciting and suspenseful story that keeps the reader in suspense until the last page. "Constant Subscriber" is a book that proves that everyone tries to find the truth, even at the cost of their own risk.