After an impossible choice is made, a flood of new proposals shine a light on the final stages of the Collaborators’ plan. Fractured but not defeated, the task force, with the help of some old friends, work to put the pieces together before the Collaborators can enact an unthinkable terrorist attack.
After Claire Haas resigned from her presidency as a result of a national scandal, it was revealed that Roarke succeeded in being appointed as the President of the United States. A week after his inauguration, Roarke signed 30 executive orders in five days and removed the cache from the internet, leading Owen to realize that the Collaborators are near their end-game. With Clay gone, Alex gets help from Will, Miranda, and Keyes to help find what Roarke is planning. Will learns that the profit made from ENGIN Industries was from the Avionics systems, which have since been added to a number of air-planes. The team finds that there is hidden code in the software that allows a plane to be remotely controlled with a smartphone if they have a popular app installed, created by a Collaborator. They realize Roarke's plan: six flights each have one person on Roarke's Muslim Registry Act, each with the app on their phone; when their phones connect to the plane's Wi-Fi, the Collaborators will use the app to control and crash the planes. Alex goes to Alice to find the flights, while Shelby, with Raina's sacrifice, finds Clay to learn the FAA's code to request emergency landing. The team successfully save the flights. However, Roarke uses the team's win as an example: he requested them to perform an off-book operation, and uses it to request a new Constitutional Convention, to rewrite the US Constitution.
- Priyanka Chopra as Alex Parrish
- Jake McLaughlin as Ryan Booth
- Aunjanue Ellis as Miranda Shaw
- Yasmine Al Massri as Raina Amin
- Russell Tovey as Harry Doyle (credit only)
- Johanna Braddy as Shelby Wyatt
- Pearl Thusi as Dayana Mampasi (credit only)
- Blair Underwood as Owen Hall
- Jay Armstrong Johnson as Will Olsen
- Hunter Parrish as Clay Haas
- Henry Czerny as Matthew Keyes
- Dennis Boutsikaris as Henry Roarke
- Elisabeth Waterson as Alice Winter
- The title of this episode, RAINBOW is a CIA cryptonym for the organization's research project on aerial reconnaissance. The project aimed at reducing radar-cross sections so that the Soviet Union couldn't detect or track the Lockheed U-2 high altitude reconnaissance aircraft.