The Pearsons come together to celebrate Kate and Toby's wedding. Wedding planners Kevin and Randall struggle to pull off the big day. Kate is flooded with memories of Jack. Deja struggles to adjust to her new living situation.
It's the Big Three's 37th birthdays. Randall and Beth debate a big life change, Kate takes the first step in pursuing a new passion, and Kevin balances the demands of his career and relationship. Meanwhile, Jack and Rebecca deal with the fallout of their big fight.
Sydney finds herself face-to-face with her mother, whose intentions for her daughter are made chillingly clear. Meanwhile 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. Dixon must decide whether or not to inform Sloane of Sydney's suspicious activities.
Lindsay's parents forbid her from hanging out with Kim, as they see her as a bad influence. Bill grows tired of being picked last for teams for baseball in P.E. class, and not being allowed to really participate.
Will's life is about to change as he is sent to find the person responsible for leaking information to him about SD-6. Meanwhile, Sloane finds himself on the cusp of finally tracking down Khasinau when SD-6 captures "The Man's" right-hand man, Mr. Sark. Dixon becomes suspicious of Sydney's activities.
Sydney, Jack and Irina must put aside their differences and go undercover as a loving family in order to seize six nuclear warheads from an unfriendly nation. Meanwhile, Sloane announces to a suspicious staff that Mr. Sark will be working with SD-6, and later he is contacted by an unknown group claiming that Emily is still alive.
Sydney gets shocking info on her dad's role in Danny's murder and takes on a countermission against the SD-6 to bring down an arms dealer linked to a missing nuclear weapon. Meanwhile, Will begins to grow suspicious of his friend's secret life; and Vaughn is taken off Syd's case after his mishap puts the entire world in danger.
Sydney's life is placed in mortal danger when Sloane is informed by his superior that she is the SD-6 mole. Meanwhile, Dixon's life hangs in the balance after he is shot on a mission, and Will realizes that his discovery of Kate Jones' pin could uncover some unexpected information.
While continuing on a mission to take control of six nuclear warheads, Sydney and Jack discover where Irina's loyalties lie when she meets up with Gerard Cuvee. Meanwhile, Sloane informs the Alliance that Emily may still be alive.
Sydney begins to question Will's identity when he's arrested for espionage, under suspicion of being a double. Meanwhile Sark and Irina plot to recover the Rambaldi heart, and Sloane makes Jack a business proposal.
Sydney tries to piece together the last two years of her life and discovers the fates of her friends and family. She confronts Vaughn about his marriage and learns the shocking fates of Jack and Sloane. Meanwhile, she is granted temporary CIA clearance on a case that may help her regain her memory.
Lauren stages a stunning betrayal to steal classified materials from the CIA. Meanwhile, Vaughn comes face to face with his darkest demons in pursuit of his wife; Nadia must decide whether or not she can trust her father, Sloane, in the pursuit of Rambaldi's most priceless artifact; and Sydney receives a shattering revelation that will make her question everything - and everyone - she thought she could trust.
"Katoby" is the best rated episode directed by Ken Olin. It scored 9.5/10 based on 2 votes. It was written by N/A. It aired on 4/12/2022 and is rated 0.2 points higher than their second-best episode, "The Train".