Lightman becomes obsessed with his investigation of two young women who committed suicide. Meanwhile, the team tries to recover billions of dollars for investors who were bilked by a Ponzi scheme.

In the wake of a building collapse in a small town outside Washington, Lightman is brought in to determine who is at fault, and he discovers a massive cover-up. Meanwhile, the team is hired by a "dot-com" billionaire to determine if his girlfriend loves him for the right reasons.

After a terrorist bombing outside of Washington, DC, FBI Agent Ben Reynolds calls on The Lightman Group to help identify those responsible and prevent more attacks. The case takes a personal turn for one member of the team and begs the question of whether honesty is indeed the best policy. Zoe helps Lightman with the investigation and both are concerned about their daughter's safety.