The Boxes was written by William Sleator in 1998. Drawing some of its material from Pandora's Box, as well as a bit of time-toying, The Boxes makes for an interesting read.
The adventure opens with Annie, who has an aunt named Ruth that owns her brother's life, by holding his annnuity. Annie's uncle, Marco looks much younger than his real age of fifty, constantly going on various trips, vacations, and absences. They live in one of the oldest neighborhoods in town, one that is about to be bought out by Crutchley Development to place a new mall in its stead. One day, Marco arrives back at home with a simple request for Annie to hold two boxes.
The boxes: one was made of rusty metal, with no marks or signs of entry anywhere. The other was wooden, also with no signs of entry except for a tightly attached lid. She was instructed to leave them in the basement, the same basement that Aunt Ruth is afraid to enter. When the wooden one is opened, she certainly hopes Ruth doesn't return...
It flowed perfectly, each event moving clearly into the next. A very clear message was present: If the power to slow time was in the hands of the wrong people, what could happen to this world? However, the book was not without its flaws(only one I could find): The ending, the final two paragraphs could have been a whole new story. Rather, they were quickly summed up in a way that left me dissatisfied.
I hope there will be a sequel.