Lightman is hired by an old friend to find a corporate spy at a pharmaceutical company, then gets mixed up in a conspiracy surrounding a new drug that could put thousands of lives at risk. Meanwhile, the State Department hires the team to assist with negotiations for the release of two U.S. citizens imprisoned in Yemen.

When a building under construction collapses, Cal and Gillian must determine if someone on the scene might have sabotaged it and how. The safety of workers still trapped inside could depend on it. Meanwhile, an Internet entrepreneur planning to propose to his girlfriend wants to know if she really loves him or if she's after his money.