Don't Let Me Go by Fanatic_weirdo
Magnus almost loses Alec and can't bring himself to leave his side.
This is such a good story because the author manages to convey a wealth of emotion in a pretty short one-shot. My heart broke for Magnus as he tried to come to terms with the fact that his beloved Alec was so close to death and what it would be like to live without him.
Even though the subject matter is pretty heavy, there is hope and some really touching moments. Give it a try!
picture credit: Freeform