Wanheda

Starts within episode 1 of Season 3, focusing on the relationship between The Last True Commander and Klark kom Skaikru. Together, they struggle to bring peace to the land and overcome a previously gruesome act of betrayal.
AU where Lexa doesn't [SPOILER] end up dead (due to a scientific miracle).

Imagine this as a novel form of Season 3, rewritten from a Clexa point of view.