Jessop is on board the Mortzestus which he soon finds to be a vessel with more than just the usual crew on board. The narration provides us with the suspense as Jessop and the other crew members experience more extraordinary events onboard the ship.
Tropes in this work:
- Ghost Pirate: Given the title this trope is appropriate here but by ghost we mean shapeless entities and by pirates we mean they take over the ship. For a book called The Ghost Pirates your expectations of a ghost pirate have never been more swerved.
- Ghost Ship: Jessop spies what he assumes to be the pirates' ship under the water. There is also a scene where they spy another ship passing by but they can't contact it, implying the Mortzestus has become one.
- Our Ghosts Are Different: Very different, in fact they may just be entities from another dimension.
- Living Shadow: How the the titular beings manifest.
- The Siege: The ghost pirates invade the Mortzestus and the crew tries to handle it as best they can, which is basically not well at all.
- Sole Survivor: Jessop ends up being the only survivor of the Mortzestus.
- Thematic Series: This book is the third installment of what Hodgson referred to as a trilogy. None of the three books share the same characters, and it's debatable on whether they're even supposed to be in the same continuity. In terms of plot and setting, the first and second books in this trilogy - The Boats of the "Glen Carrig" and The House on the Borderland, respectively - don't have all that much in common with each other.
- Things That Go "Bump" in the Night: Some of the book's earliest encounters with the entities are played out like this, with people on deck hearing footsteps where there shouldn't be any.