A South Florida middle schooler faces monsters in his quest to save the Land of the Living from the Land of the Dead in this riveting latest series installment. It's just an ordinary school day until a calaca, an undead skeletal being who ferries the deceased to the underworld, shoves Charlie Hernández into the girls' bathroom. Because he is a Morphling, a kid who can manifest animal characteristics as per Latinx myth, the calaca claims Charlie is the only one who can save her sister from unknown villains. She refuses to provide more than scant, cryptic clues, claiming it's too dangerous. When they are almost caught by a teacher, the calaca pulls her bones apart and flushes herself down the toilet in a delightfully creepy scene that is just the beginning of many unexpected twists. Assisted by longtime crush Violet Rey and Raúl, a cousin from Mexico who's staying with him, Charlie embarks on a whirlwind adventure to help the calaca, figure out why cafeteria aides have gone missing, and determine the cause of recent unusual earthquakes. The quest takes him to real Miami sights, from a centuries-old Spanish monastery that doubles as a Witch Queen's study to the Venetian Pool where reptilian heavies wait to attack. Charlie defeats magical enemies at every turn, all while charmingly balancing ordinary issues such as friction with his cousin and his first love. The plot thickens when deceptions and connections between all the mysteries are revealed. Clever, funny, and entertaining. (Fantasy. 10-14) Copyright (c) Kirkus Reviews, used with permission.