Castle Backstabber (2009–2016) Online
After planting a spy bug for a private job, Hayley sneaks off while her partner Marcus Janek stays hidden to spy on the lovers couple in another office that nearly caught them. Next morning, team Castle, with Hayley tagging along, investigate a murder in the same building and find the victim is Marcus. Hayley stays silent as long as possible but must come clean when another murder is found. Meanwhile, the case is found to involve cyber-terror in London and MI6 dispatches agent Steven Mallory, who duly treats her as prime suspect.
| Episode cast overview, first billed only: | |||
 | Nathan Fillion | - | Richard Castle |
 | Stana Katic | - | Kate Beckett |
 | Susan Sullivan | - | Martha Rodgers |
 | Jon Huertas | - | Javier Esposito |
 | Seamus Dever | - | Kevin Ryan |
 | Tamala Jones | - | Lanie Parish |
 | Molly C. Quinn | - | Alexis Castle |
 | Toks Olagundoye | - | Hayley Shipton |
 | Alan Smyth | - | Agent Steven Mallory |
 | Aaron McCusker | - | Wesley Connors |
 | Bree Williamson | - | Karla |
 | David Hoffman | - | Ned Werner |
 | Oliver Muirhead | - | Bryce Robert |
 | Michelle Alegria | - | News Anchor |
 | Senta Burke | - | Cleaning Lady |
The day this aired, ABC announced that, if or when the series was renewed for season nine, Stana Katic and Tamala Jones would not be returning. The decision to not renew their contracts was eventually rendered moot when the series was canceled the following month.
Bree Williamson appeared on Liebe, Lüge, Leidenschaft (1968) as Jessica Buchanan, sister to Nathan Fillion's character Joey Buchanan.
Largely because of the reaction to the news Stana Katic would not be returning for a ninth season, this is one of the lowest-rated of the season, and the lowest since "Castle: G.D.S. (2016)".