There's a rip in the blue umbrella, and time—and Chelsea—are slipping through!

One moment she was there, the next moment she was not, and Ches Cholmondeley was watching when it happened. And he learns of other mysterious goings-on: for three days in a row the world's atomic clocks have lost a second, resulting in bizarre accidents ranging from dropped casseroles to plane crashes. Are these events related? What's a brother to do?

Figure out a way to get his sister back, of course. In search of answers, Ches befriends the local clockmaker, Myron Stinchcombe, who knows a lot about time, and seeks out Sky Porter, who knows a lot about, well, everything.

But time is running out. And Ches is torn, knowing that the very deed that can save the world might also keep his sister from ever returning to it.