This is a great Locked Room Mystery in Space.
The locked-room mystery is a subgenre of detective fiction in which a crime — almost always murder — is committed in circumstances under which it was seemingly impossible for the perpetrator to commit the crime or evade detection in the course of getting in and out of the crime scene. Wikipedia
The Dormire is a ship holding hundreds of colonists, sleeping as they move through space towards a new home. The Dormire has six crew who are awake at all times, monitoring the ship’s passage and the vitality of the colonists.
Cloning has made it possible for the crew to make it through the journey over the long span of time required for the trip. They have set copies and can call those up when the time comes to retire their current bodies.
As the story begins, all six crew have been murdered in horrible ways. They’re bringing their clones online in an emergency reboot. The new clones have no memory of what happened to them, who killed them, or why. The gravity of the ship is offline. The ship’s AI, which should have a full record of events is barely functioning. The ship’s original Captain is barely alive, and is unresponsive.
Clone law states only one version of a person may exist at once, and the new clone always has precedence. The old clone must be disposed of immediately. Everyone understands this, but some feel the earlier captain can give them vital information, such as who killed everyone and why. Will the killer get to her first?
A further problem is that all the crew’s clone backup information has been wiped. They cannot be cloned again, revived again. Anyone who dies to the killer a second time will be permanently dead.
The crime scenes are grisly. Noone can trust anyone else. They still work together to find answers and to get the ship back on course. Inexplicably, it is now on a heading back toward earth, and they cannot get that changed without a working AI.
Every page is tense and action packed. You see how everyone got where they are, and at one point, it has that Murder On The Orient Express quality where it looks like every single person is the murderer.
I love mysteries and I love science fiction, this is a perfect blend of both. I wish the author would write many more terrifying, suspense filled stories like this one.