Reborn in 1993, Dark Sea

[Rebirth + Suspense + Undercover + Revenge + Anti-Drug + Anti-Espionage, with very weak cheat abilities, relying on one's own skills, high-IQ battles, requires brains, no face-slapping or overpowered moments! Suitable for experienced readers, very enjoyable if you understand it; impatient readers and those looking for mindless enjoyment should proceed with caution, as skimming will not be easy to understand.]
Thirty years ago, An Xiaohai was framed and accidentally killed someone, ending up in prison and falling from the peak of his life to the bottom!
Twenty years of dark and hopeless imprisonment ravaged him beyond recognition! After his release, he struggled for ten years before dying in despair.
An Xiaohai transmigrated into the body of his past self thirty years ago. Heaven had given him a second chance at life, and An Xiaohai didn't want to miss it again! Why was he being targeted like this?! Why was he being treated so cruelly? Why wouldn't the mastermind behind it all let him go?!
An awakened An Xiaohai did his best to expose the many dark secrets!
Having been given a second chance at life, I must pull myself together! I must clear my name! I must take control of my destiny!
An Xiaohai navigates various dangers, and as he unravels the mystery, one conspiracy after another is exposed, and a huge shadow gradually emerges!
An Xiaohai is no longer the weak lamb he once was. Watch how he turns the tables in a desperate situation and turns the tide!