I know it's a spoiler but it's not much anyway so yeah, apparently, Mikan used up what's left of her alice to save Natsume's life but unfortunately, it ended in vain. Y'all can theorize o guess what's after that because it might be a big culo spoiler.
Anyway, this information came from a spoiler thread on the magafox forum so I'm not really sure if it's accurate (especially since I only read a bit of it in order to avoid further spoiling).
I think we all just have to wait for the future chapters in order to find out. :3
He can't be dead! He is awesome and i believe that she (Mikan) was able to save him with her power! I just hope that they can be together again! I also think he knows she saved him so Natsume! DON'T GIVE UP ON LIFE!
HE CANNOT BE DEAD!!! it would be too cruel if he was!!! this series is super sad so it has to have a happy ending to make up for all the tears it has cost people!!! besides Hotaru is awesome and would never ever fail Mikan... ever!!!! Natsume is a pansy but everyone is waiting for him so he has to live o go down being called the biggest jerk of all time!!! mm-hm!!!
No, Natsume is alive!!! :) hotaru sacrifice herself and her brother too! When hotaru, her brother and nodachi sensei went to the past and hotaru's brother healed natsume and he is alive but their is a consequences for doing that. This is when after she want to see Mikan for a final good bye! :'(
Look, He died when he used too much of his alice, whe all know that he has the limitless form and it makes hs life be shorter each time he overuse his alice. At that time he uverused to much, making he dead at instant. Mikan made the offort of her alice in vain because Natsume was already dead when she came, cuz he died INSTANTLY. Hotaru, seeing her best friend too sad goes to the time travel to resurrect Natsume which after too much chapters, we see him alive again, but unconscious. Becasue of that Hotaru and Subaru are trapped on the Time Travel. now.. sorry for spoiler... *SPOILER* Years later, we all the gang 4 years older and after making mikan remember them all, Natsume, Ruka and Mikan go to the time travel to cerca for her, something we cant see because Higuchi-san finished the manga before, but it all written in the dialogs. Higuchi-san is making a Memory book with special pictures we couldnt get so see at the manga at past, present and future. Its THERE were we see again Hotaru, sicuro, cassetta di sicurezza and sound.