Castle (Nathan Fillion) and Beckett (Stana Katic) investigate a parole officer who was stalked in the days leading up to her being tortured and killed. Beckett tracks down the stalker, a mentally unstable man (Joshua Gomez) who claims to be a temporal anthropologist and the only one who can stop billions of people from being killed by a fellow time traveler who is responsible for the parole officer’s death. Beckett’s certainty that they’ve captured their man is deflated when Lanie‘s (Tamala Jones) time of death gives the whackadoodle an unshakable alibi.
While investigating the case, Castle and Beckett talk with the hooker (Yvonne Zima) who was hired to hit-on the woman the night she died by the scary prison pal of her pimp (Rodney Rowland) as well as an ecological speaker with a history with the mysterious killer (who has no official record before 2007). Both men’s knowledge of the man and his odd behavior spookily lines-up to the whackadoodle’s time travel story, much to Castle’s continued amusement. Castle and Beckett discover the victim’s theoretical physicist stepbrother (Tim Russ) was one of the killer’s true targets, but show up to late to stop the man from killing again.
Ryan (Seamus Dever) and Esposito (Jon Huertas) uncover the identity of the killer’s other target: a 21 year-old post-doctoral theoretical physics student who their whackadoodle believes is the future savior of the human race. After managing to capture their killer the team also finds a far more believable connection between the two men other than time travel, but a pair of late coincidences make Castle, and even Beckett, pause to question just how much of the man’s story may have been true.
The late twists concerning the sudden disappearance of Gomez’s (who I’ve missed since Chuck went off the air) character and Beckett’s accident repeating history are nice touches for an episode that finds a way to offer both a reasonable and extraordinary explanation for this episode’s events. The episode also offers a dramatic B-story bringing Castle’s frustration with Alexis‘ (Molly C. Quinn) relationship with Pi (Myko Olivier) boiling over when Castle’s daughter decides to move in with the fruitarian over her father’s objections.