Complex sentence: In Five Years Gone, Mohinder shows the past Hiro Nakamura the comic book and tells him that the events in the book show that Hiro kills Sylar in the past, but this had not happened in the future that they were in.
Split into simpler sentences: In Five Years Gone, Mohinder shows the past Hiro Nakamura the comic book and tells him that the events in the book show that Hiro kills Sylar in the past. This, however had not happened in the future that they were in.