Nathan Fillion's character, Castle, mentions that his first novel was inspired by One Life to Live (1968). Fillion played Joey Buchanan on the daytime soap from 1994-97, with a short reprise in 2007.
When Castle and Beckett return to the precinct after questioning Mr. Peterson about his alleged affair with Sara, Ryan can be seen at his desk flipping through one of Castle's books.
Two political ads for City Councilor are seen as Castle and Beckett are going to the playground to talk with Chloe Richardson. Jason Bollinger's campaign poster is on a pole and Jeff Horn's political ad is on a trash can. These are the two candidates in HELL HATH NO FURY.