Hiya!

This will take place in Blue Lions Route so be warned by SPOILERS
You and your sister Selina becomes students at Garreg Mach not knowing the real story of your parents lives. You've been orphans and raised by mercenaries since then. Once it gets closer to the war both have been investigating the connection of their parents to the Adrestian Empire.
And of course there'll be some good ol' romance between you and the Blue Lions.