Alice Butler has been receiving some odd messages - all anonymous, all written in code. Are they from someone at PopCo, the profit-hungry corporation she works for? Or from Alice's long-lost father? Is someone else on her trail? The solution, she is sure, will involve the code-breaking skills she learned from her grandparents and the key she's been wearing around her neck since she was ten. PopCo is a grown-up adventure of family secrets, puzzles and the power of numbers.