The ""Mystery Cat""--M.C. for short--is a streetwise tomcat with a taste for adventure. Wherever M.C. is, there's sure to be trouble. By day, he belongs to Kelly Ann McCoy, but he spends his nights with Hilary Barnett, and each girl thinks he's her pet. When they discover they both own the same cat, they decide to share him--and that's when the action begins. When M.C. returns from his daily food run between his two homes, he drops some funny money at each girl's house. Hilary and Kelly Ann decide to trail M.C. so he can lead them to the counterfeiter, but the plan backfires and Hilary ends up in a trap. Only M.C. and Kelly Ann can save her in time--as they lead the police to the counterfeiter's lair. Mystery Cat starts out slowly, though it picks up the pace once the girls begin their search for the counterfeiter. But the plot is fairly predictable and readers will have little trouble figuring out the story's end ahead of time, which significantly cuts into the narrative's attempts at suspense. Christelow's black-and-white illustrations are lackluster and don't add much to the enjoyment of the story.