The overall show has a general metaphor referencing Moby Dick. Where Ahab obviously parallel Beckett in her obsession to catch her mother's killer, as well as parallelism between Ishmael and the Castle character. Both Ishmael and Castle are observant characters who embark onto a journey from Manhattan. (Let's hope they don't follow the plot closely with Moby Dick or a lot of our favorite characters on the show are going to be hurt!). The writing of the show is also filled with the complex symbolism and metaphoric style as in Moby Dick, filling different epsiodes with small forshadowing and hints about the bigger theme that deeply intrigue the audience.
- Season1: Home is where the heart stops
At the museum charity event, Castle was referred by the women as the "Great white whale"
- Season3: Slice of Death
Cavalo was referred to as the "White whale". Ahab was also referenced several times in this episode.
- Show Intro sequence: "I'm Castle"
The intro sequence starts with Castle introducing himself as "Who am I, I'm Castle". Similarity with "Call me Ismael"?