The story focuses on young doctor Leta Adler who is swept aboard the beat-up spaceship captained by exile and notorious criminal Fiearius Soliveré. Though initially out of place amongst the crew, Leta grows to identify with them, particularly in their mutual hatred of the Society, an extensive and morally questionable organization gradually taking over the Span.
It's divided into three parts and officially finished.
Caelum Lex contains examples of:
- Anti-Hero: Fiearius Soliveré is, on the surface, a smuggler, a thief and an assassin that only looks out for himself and his own, but on occasion, performs heroic acts.
- Dark and Troubled Past: Before leaving his home planet on the Dionysian, Fiearius Soliveré worked as an assassin for the Society, potentially murdering many innocents. This culminated in an event that caused both his wife and four year old son to be killed
- Defrosting Ice Queen: Leta Adler is depicted as cold, stern and unflinching towards Fiearius, but in time she warms up to him and even comes to love him.
- Determinator: In Part 1, Leta wants Ren back. At any cost.
- The Empire: The Society is so evil it's hard to wrap one's head around why any planet would want to join it, instead of nuking their diplomatic ships on orbit.
- Fish out of Water: When Leta initially boards the Dionysian, having been raised in wealth and luxury on her home planet, she does not fit in with the criminal crew nor understand their activities and methods. But she takes to it Like a Duck Takes to Water.
- Gadgeteer Genius: Cyrus Soliveré and Adrasteia Atelier, both engineering prodigies, consistently override security protocols, wrangle together engine pieces and build any gadget needed for a specific mission.
- Hangover Sensitivity: Averted. Nobody seems to get properly hung over, even in the What Did I Do Last Night? scenes. And they drink a freakin' lot.
- Hidden Heart of Gold: Fiearius Soliveré emits a jerk persona to appear strong to his crew, worthy to his criminal allies and indestructible to his enemies. This bites him hard in the ass in Part 1 when the crew, tired of not being told a thing, mutinies and Aiden, the voice of reason on board, is accidentally killed in the struggle.
- MacGuffin: The titular Caelum Lex (Latin nerds, please stop flinching) is a memory core for a terraforming machine, which contains all the procedures needed to terraform a planet - think the Genesis Device.
- Nerd: Cyrus Soliveré is a prodigal engineer who loves his craft with passion and spends a great deal of time nerding out about engines, sometimes with fellow nerd Adrasteia Atelier.
- The Smart Guy: Cyrus, the Dionysian's engineer and resident tech nerd, is often one step ahead of everyone else, coming up with ideas and plans and solutions that no one else on the crew considered.
- Space Pirates: The crew of the Dionysian, natch.
- What Did I Do Last Night?: One memorable instance of this includes Fiearius waking up next to Leta or actually, Rochelle, who looks a lot like Leta and he's confused for a moment.
- Worst Aid:
- Soap Opera Disease: Both Fiearius and Leta, who's supposedly a doctor! work through their illness as if there were no tomorrow. He runs around delirious for weeks in Part 1.
- Fantastic Drug: Flush is amphetamine Up to Eleven. ARC treatments involve something pharmaceutical for Bedtime Brainwashing and Fake Memories planting.
- Magical Antibiotics: With a flip-flop as to whether they're easy to get or only available in Society hospitals.
- Magic Antidote: When Cyrus gets poisoned in a bar, all Leta has to do is induce vomiting and there's nothing wrong with him afterwards.
- We Have to Get the Bullet Out is never questioned, not even by Leta, the prodigy trauma surgeon.