Question about Black Butler season 2 (Kuroshitsuji II)?

So I just finished Black Butler, the first season. I was a little disappointed on how it ended. I was reading about the second season and it sounds like Sebastian and Ciel are also in that? How is that possible? Is there a way to tell me without giving any spoilers? I sort of ruined the first season by looking up spoilers. I'm just curious as to how all of that works out?