Basically it's a Post Heavens Feel Shirou who has killed both Sakura and Saber, most of the people(well more than canon that is) of Fuyuki have died including Taiga, Issei, and Ayako etc. Shirou sees Rin as a friend nothing more nothing less, Rin then asks Zelrecht to send him to another world seeing as this world takes from him and makes him sad or something like that and Zelrecht agrees due to being bored and this will provide him with the necessary entertainment he needs, so he sends him to the Absolute Duo world, Shirou wakes up and thinks that this is a prank from Zelrecht and knowing he'll be here a while he might as well get an education so he signs up to Kouryou Academy thinking it's a regular school. Anyway I don't need say more the only mandatory thing is that he pairs up with Julie Sigtuna if it's a single pairing if it's a double pairing then as long as it has Julie I don't care if it's a harem as long as it has Julie I don't care.
