After Ziva's apparent death, Tony raises their daughter Tali. Years later, Ziva returns, and reunites with Tony. Tony's company is attacked, the family goes to Europe, trying to learn who's after them and to trust each other again.
Jim Phelps is the new leader of the Impossible Missions Force, with no explanation, or even reference made, about the departure of predecessor Dan Briggs. First up for Phelps is a mission involving the drug trade. Cresnik and Walters have cornered the heroin market and sell it at a handsome profit to gangs around the world. Phelps devises an operation which will drive a wedge between the heroin dealers and their customers.
Sydney finds herself face-to-face with her long-lost mother, Irina Derevko, whose intentions for her daughter are made chillingly clear. However, Sydney manages to escape and rejoin Jack and Will in their escape from Taiwan. After arriving back in Los Angeles, Sydney continues her search for Vaughn, not knowing if he is dead or alive after being swept away by a wall of water in Taipei. Will's life is forever changed when he learns the truth about SD-6 and Sydney's life as a double agent. Also, Dixon must decide whether or not to inform Sloane of Sydney's suspicious activities. But Jack intervenes and covers for Sydney who later finds Vaughn who helps her try to track down her mother Irina who's searing for a Rimbaldi artifact called 'the Bible.'
A group of aliens has come to Earth to learn about its population, customs, etc. To avoid detection, they have taken on human form which gives them human emotions, physical needs etc. WITHOUT the understanding of what they mean or the inhibitions normally present in humans. Their leader takes the position of a college professor, their military expert as his sister, their intelligence expert, supposedly oldest of group takes form of his teenage son. The uninhibited reactions turn everyday events into unusual situations.