When two separate murders are committed on the same night, Castle wagers Ryan and Esposito that he and Beckett will solve theirs first. The frenzied race to catch their respective killers and win the bet leads each investigative duo to a likely suspect, only to find that they both have airtight alibis. But bizarre twists in both cases force the two teams to work together to unravel the mind-bending mystery behind each murder.
Peter faces unexpected consequences for his heroic acts and encounters a reluctant new hero. As Claire continues to adjust to college life, she must figure out how to deal with her ability having been revealed. Meanwhile, Samuel moves heaven and earth to recapture the memories of his late brother Joseph. Elsewhere, Matt struggles with his internal demons as Sylar mysteriously resurfaces.
Barney takes Marshall, and Robin to a strip club where they find a stripper who looks almost exactly like Lily. Meanwhile, Ted discovers he had been fixed up with the same woman, Jen seven years earlier.
Cal is approached by a young woman who claims she saw a murder in a vision, but the police won’t believe her. Meanwhile, Ria interviews a Supreme Court nominee for the White House to determine if there are any skeletons in his closet.
It has been several months since Alpha’s reign of terror and Echo, who is now randomly picking up flashes of past engagements, weds a British businessman who has ties to one of Ballard’s open FBI cases. Topher becomes the target of Dr. Saunder’s aggression after she finds out that she is actually a doll named Whiskey. Boyd takes on a risky venture and mixes business with pleasure, while DeWitt makes Ballard an irresistable offer.
Jane and Lisbon learn that the Red John case has been reassigned to a different CBI team led by the straight-shooting officer Sam Bosco.
Jeff’s attempt to become Britta’s Spanish project partner fails and he ends up with Pierce. Shirley and Annie help Britta with a social justice cause.
A series of strange disappearances in Pennsylvania attracts the attention of the Fringe team and leads them underground.
Walter also tries to recreate Olivia’s accident using frogs and Charlie tries to find out how much she remembers.
Jay is having trouble keeping up with his new young Colombian wife and her son. Claire is having trouble with her husband Phil, who thinks he can be hip with their kids. Mitchell and his partner Cameron adopt a Vietnamese baby.
Alicia returns to work as a defense attorney after her husband’s corruption scandal and incarceration. She is assigned her first case – a retrial of a woman accused of murdering her ex-husband. Her firm successfully deadlocked the first jury, and they hope that sticking to that strategy will work again, but Alicia realizes that this trial will be more of a fight than anyone expected.