The Vanderbeekers: The Vanderbeekers and the Hidden Garden, Book 2 by Karina Yan Glaser

While Isa is off at sleepaway orchestra camp, Jessie, Oliver, Hyacinth, and Laney are stuck at home in the brownstone with nothing to do but get on one another’s nerves. But when catastrophe strikes their beloved upstairs neighbor, their sleepy summer transforms in an instant as the Vanderbeeker children band together to do what they do best: make a plan. They will create the most magical healing garden in all of Harlem.