Intended adult novel for beginners

Hi, i decided to start to read books for good stories with good plot. I am new to English novel reading and also its aint my first language. Since writing been into this world for a quite a while i can assume there are so many good stories lying around there with such good plots and story that i dont knew.
Do you have any suggestions for a beginner. Honestly what ever you suggest i want something really good and easy to read if possible. Also intended for adult, by this i tryna meant like it might have mature themes and honestly i don’t mind it , kind a want stuff with mature theme. I personally like medieval themed stuff , like story based on old times.