Caroline accidentally stumbles upon Max's secret ingredient for her cupcakes while dealing with her new couponing obsession.
Brennan and Booth stumble upon a subterranean world of homeless people when they find the remains of a filmmaker in the ventilation shaft of an underground tunnel.
When a five-year-old girl is kidnapped from her birthday party, Don and Terry lead the investigation. They must, however, rely on Charlie's help because the girl's father Ethan is also a mathematician. Charlie realizes the kidnapper's motive when Ethan reveals he is close to solving Riemann's Hypothesis, a difficult math problem. If solved, the solution could not only earn him $1 million, but could break the code for Internet security and unlock the world's biggest financial secret.moreless