"Altered Carbon" is a ten episode Netflix series based on the 2002 science fiction novel of the same name by Richard K. Morgan. The main character is Takeshi Kovacs (Joel Kinnaman), who was dead for 250 years after he took part in a failed revolution. He is an "Envoy," the last one available to be revived, and now Laurens Bancroft (James Purefoy) has brought him back to solve Bancroft's murder. What makes both of these things possible is the "cortical stack," a tiny device implanted at the base of the skull that holds all of a person's memories when it's moved to another body (bodies are called "sleeves"). If, that is, you can afford another body. Bancroft is a "Meth" - a person so rich he can live forever, like Methuselah. Kovacs is unimpressed by the world he's reborn into, and appears about to decline the invitation, but a flashback to the leader of his revolution convinces him to stay. Flashbacks are a big part of the series, filling in Kovacs' and the revolution's backstory.
I haven't seen Kinnaman in much, but haven't really been a fan. But this seems to be the role he was born to play: a gritty, disaffected anti-hero with a conscience who doesn't give a shit about anyone. The person he spends the most time with is Kristin Ortega (the beautiful Martha Higareda), a strong-willed cop Kovacs finds himself tangling with repeatedly. She's also quite good. I also greatly enjoyed Edgar Poe, the A.I. proprietor of the hotel Kovacs stays at (where he's the first guest for 50 years). Poe becomes a surprisingly important character. I thought the last couple episodes were a bit over-the-top with the return of another apparently-dead person: certainly the cortical stack allows for this, but the changes in the person are ... extreme, and not - to my mind - entirely justified.
Morgan has created a particularly thought-provoking mental playground with the implications and problems of the cortical stack: what does it mean when anyone can be "resleeved" at any time? Cross-gender, different age ... someone that other people recognize as someone else? He chooses to explore the ideas with more violence and action than I thought was necessary. It was also darker than I liked, but the darkness was justified by the massive economic disparity created by practical immortality.
The first episode was okay, but didn't entirely pull me in: watch the second episode. If that doesn't get you, then ... you may leave. But if you're a fan of SF, I think you'll be staying: this is the golden age of SF movies and TV, and this is one of the better ones out there.