After a beautiful clock is stolen from the Mahoney Library, Nancy must take a break from planning the libraries' seventy-fifth anniversary, and solve the mystery.
Grandpa and Cayley have built many clocks together, but when grandpa has a heart attack and ends up in the hospital, the family has to help him heal before anymore clocks can be made.
Bernie Bridges, the egotistical planner and schemer for a group of fourth-graders at The Rotten School, is determined to outsmart his rival in a pie-eating contest.