What will the twins get into next? A man. A moth. A flying mystery. The legend of the Mothman is back in the news. He's been seen flying overhead. Wreaking havoc everywhere he goes. What happens when Grace and Henry's parents want to join them on the ghost hunt? The Warner family is challenged to keep it together as they all have different ideas about what is going on and how to find answers. Grace and Henry Warner return with a new folder for the monster case files, a file soon to be filled with clues, facts, and guesses. Join the twins on their journey through a life of travel and mystery with parents who believe in them, as long as they aren't completely sure what the twins are up to.