A bleeding man stumbles into a church, but just before dying, he hands a mysterious bundle to the priest. When the bundle turns out to be a smiling baby boy, Castle and Beckett find themselves accidental nannies to the newborn. But when they determine the baby and the victim were not related, they discover that finding his rightful parents may be just as hard as solving the murder.
Marshall tries to get Marvin to sleep by reciting three rhyming bedtime tales about his friends as they wind down their epic cross-country journey.
Carrie reunites with Brody, but the circumstances are more difficult than either of them could have imagined. Meanwhile, Saul gets a win from an unlikely source, and Dana grapples with her new life away from home.
Alicia tries to hold a website accountable when its users accuse her client, a college professor, of being linked to domestic terrorism. Meanwhile, Will goes against Diane’s wishes when he hires Damian Boyle, an unpredictable attorney with ties to organized crime, who immediately interjects himself into Alicia’s website case. Also, Eli and Jackie clash over a Florrick family secret.
Patrick Jane finally comes face-to-face with Red John, the serial killer he’s tracked since the madman murdered his wife and daughter. For 10 years, Jane has doggedly hunted his nemesis in his search for justice.
Holmes and Watson uncover the identity of a serial killer whose case has gone cold and find themselves butting heads with the NYPD.
Peter and Neal must go undercover as ice skating pros to expose a counterfeit passport ring in Little Odessa.
Olivia and the team try to handle both uncovering the truth behind Operation Remington, while also managing a potential crisis with the Josie Marcus campaign. Meanwhile, Quinn falls further down the rabbit hole with Charlie, and Cyrus creates a plan to take down Sally, but doesn’t think of the possible harm he could inflict on himself.
Claire encourages Jay to go to ClosetCon, where he is reunited with former colleagues; for the first time, Cam takes Lily and Mitch to the Tucker farm.
Oliver is concerned when a mysterious illness sweeps the city, infecting hundreds of people, including Diggle. Oliver discovers Vertigo in Diggle’s blood and realizes The Count has broken out of prison and is once again distributing his drug. Meanwhile, Moira goes on trial for her participation in the Undertaking. ADA Adam Donner collapses in court with Vertigo symptoms so Laurel must step in and try the case against Moira. Oliver is torn between standing by his family during the trial and catching The Count. However, things change when Felicity follows a lead and walks straight into a trap set by The Count.