In 2018, Russian spy Sergel Skripal and his daughter Yulia were poisoned by nerve agent Novichok, one of the deadliest substances on earth. Police, doctors, and eye witnesses recall the events that devastated Salisbury and shocked the world.

An elite team of FBI profilers analyze the country's most twisted criminal minds, anticipating their next moves before they strike again. The Behavioral Analysis Unit's most experienced agent is David Rossi, a founding member of the BAU who returns to help the team solve new cases.