A trip to the Revere Public Library proves fatal for thirty-six-year-old Yolanda Fiore. Her body is found early one morning at the bottom of the library's staircase. The evidence shows she'd been struck on the back of the head before her fall.In this fifth Periodic Table Mystery, retired physicist Gloria Lamerino is not inclined to take on another murder investigation - her romance with homicide detective Sergeant Matt Gennaro is all the contact she needs with the Revere Police Department.But Gloria will do anything for her lifelong friends and current landlords, Rose and Frank Galigani, operators of the Galigani Mortuary. So when their son John is arrested for murdering Yolanda, his former girlfriend, Gloria goes in search of the real killer.