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When a five-year-old girl is kidnapped from her birthday party, Don and Terry lead the investigation but must rely on Charlie's help, as the girl's father, Ethan, is also a mathematician. Charlie realizes the kidnapper's motive when Ethan reveals that he is close to solving Riemann's Hypothesis, a difficult math problem. If solved, the solution could not only earn him with $1 million but could also break the code for Internet security, unlocking the world's biggest financial secret. Neil Patrick Harris guest stars.

  • Runtime: 43 min
  • Quality: HD
  • Studio: CBS
  • Amazon rating: 4.5

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