When I sat down this past Sunday for the mid-season premiere of The Walking Dead, I didn’t unplug like I normally would. Instead I kept an iPad at my side, and while Rick Grimes, his son Carl, and the sword-wielding Michonne battled their way through a zombie apocalypse, I took part in polls, reminisced about older episodes, and got a glimpse of what was yet to come. It was courtesy of AMC’s Story Sync, a custom app and web experience designed just for that network. While second-screen viewing can often feel like the great promise that’s never quite delivered, AMC is doing everything it can to buck the trend — and it feels like it’s succeeding.