When it comes to crack TV, AMC's massively addictive series "The Walking Dead" reigns supreme. The shorthand description would be "zombie-apocalypse survival thriller," and that's true enough, but it goes deeper too. If you take away law, religion and society — what's left? Can such things as compassion or morality exist in a brutally Darwinian world? If all that's left is killing to survive, then what's the difference between us and the ravenous undead? In that sense, "The Walking Dead" is intensely concerned with what it means to be human.

While the zombie special effects are wonderfully gnarly and the suspense is at times unbearable, what really hooks viewers is the performances from the show's remarkably strong ensemble cast. Its two most popular stars, Andrew Lincoln and Norman Reedus — who play morally conflicted cop Rick Grimes and bad-ass biker Daryl Dixon — were in Tokyo recently to promote the Japanese airing of Season 4, which begins on Fox on Sunday, and sat down to chat with The Japan Times.

As Season 3 moved into Season 4, characters were killed off with such impunity it began to feel like a very real possibility that the series would end when everyone was dead. The loss of beloved characters always comes as a shock to the viewers, but how is it for the cast?