Merlin is attacked and won't tell Arthur anything. Arthur likes Merlin, his hand servant for almost 2 years, it breaks his heart to see Merlin this beat up and hurt. Arthur is trying to do whatever he can to forward his relationship with Merlin, while he tries to find out and understand what happened to his brunette servant. [Please comment and tell me if this is a good story or not, ok? Thanks!]

[Au] Gwen never becomes Queen because she chooses Lancelot and Lancelot chooses her (During Lancelot and Guinevere [s2e4] not during Lancelot Du Lac [s4e9]). Arthur is a bit hurt but not too torn up about it. Actual fanfiction starts towards the end of "Death Song of Uther Pendragon" (s5e3).

Merlin dies for a bit at the end of the series instead of Arthur.