I enjoyed this author’s “Mysterious Benedict Society” series, which I felt grew better as it went along. “Secret Keepers” has all the attractions of Stewart’s earlier books like puzzles and mysteries with the addition of a setting filled with ominous dread and tension that ups the excitement.

Reuben is a loner, a boy living with his mother in a poor part of the city of New Umbra, a city controlled by a menacing mystery man known as “The Smoke,” who no one ever sees. He’s a sort of crime boss with a network of thugs collecting bribes all over the town. Police and government officials fear him too, and are unable to stop him. Reuben likes to explore the city on his own, and has become very good at doing so without being noticed. His mother worries about him, and wants him to make friends, but Reuben is happier playing solo spy games. At least until he finds a very unusual watch. The watch has the power to make him invisible for a short time, though he becomes blind when he does so. Before long he is using it to spy on even more shady characters, but somehow The Smoke has found out about him, and his henchman are searching the city for the boy. Reuben must get away, and his destination is a lonely lighthouse on the coast where even more surprises and secrets are uncovered, and new friends are found. Even with his magic watch, though, can Reuben and his new friends Jack and Penny do anything to protect themselves from The Smoke? You see, he has another watch just like Reuben’s, and is desperate to have them both.

Recommended.