The Knight and her Princess

In the war between countries and lands there is a certain Princess name Eli, the oldest daughter of the King of the Shinju kingdom, she has daughters named Maki and Honoka. Then when a certain knight came into the oldest daughter of the King, her life changes. Until one day, the King decided to arrange a marrage for Eli and a certain Prince on one of their allied country. What will happend to the Knight she really love? What will happend to there time they spend as 'lovers'? Will the healer Kotori can have a chance to get Shirei...