Fun early entry (#4) in the Discworld series. Death (capital D) has been working on the Discworld since its creation. It is his job to gather souls at death (small d) and pass them along to wherever they go. He doesn’t know; he doesn’t take sides; it’s just a job. He is good at it and you always know when he is speaking to you because he has the distinctive voice of FINALITY. (Pratchett’s Death always speaks in capital letter.) But he is dreadfully bored and thinks it is time for an apprentice, so he can take a break once in a while. He chooses a teenage boy suitably named Mort (short for Mortimer) to learn the ropes … or maybe “the scythe.”
After some training, Death turns the soul-gathering over to a not-quite-prepared-enough Mort. Death heads to a job service to look for something new to do, while Mort sets out for his collection duties. Unfortunately Mort determines that a beautiful princess should not be assassinated, so he prevents it from occurring, thereby creating two versions of Reality. Clever confusion ensues.
Not in the top tier of Discworld books, but entertaining.