The Phantom Friend

What do you mean? Judy asks her new friend, Clarissa Valentine. How could you look in a mirror and not see your reflection? When Clarissa insists that this strange thing has happened to her, Judy and the other girls think she is teasing them. But when Clarissa disappears in the middle of a television show, even Judy has to admit something peculiar is going on. The three other girls are angry, because with Clarissa went the twenty dollars they had loaned her. But Judy still believes in Clarissa, though something certainly is very wrong. Judy wishes her FBI husband, Peter Dobbs, would complete his mysterious mission and join her in New York City. She wants him to help her find the young girl, who might be in real danger. What Judy does not know is that Peter himself is in danger. The next time she sees him, he is lying injured in a hospital bed. But by a weird combination of circumstance, what happens to Peter gives Judy her first clue to what might have happened to Clarissa. When Judy, with Peter's help, finally learns what really did happen, she uncovers a mystery far more exciting than she could possibly have imagined. (Goodreads)