Back to Time by samyazaz
Connor receives news that Oliver has been in a an accident and is serious condition. Even though their relationship is pretty much nonexistent after the revelation of Connor's cheating with Pax, he can't help but run to the aid of the man he's too afraid to admit he cares about. When Oliver finally awakes and has amnesia, Connor can either walk away or pretend to be his loving boyfriend.
It's nice to go back and read fanfic from the early years when HTGAWM had just started and Coliver was just beginning to gain steam. This is a great example of story that pulls you into the lives of the characters and makes you feel every emotion that rips through them. Check it out!