The Thirteenth Step: Thriller book for kids

Oakhaven is a town of perfect circles and silent secrets, where every staircase stops at twelve. When Leo Thorne’s brother vanishes into thin air, Leo discovers a terrifying truth: a hidden thirteenth step exists, acting as a gateway to a faceless ＂Echo-World＂ that is slowly devouring his town. To save his family, Leo must break an ancient, rhythmic curse by facing the horror of the stairs and proving that human grief cannot be measured by a number.