Five mentors?

What if there was a fifth member in Quartet Night? This fifth member has known the others forever. Oh and one little thing. This fifth member is a girl. She preforms with them as well is their composer. What happens when Shining asks the group to mentor Starish? Sophie is assigned to Nanami Haruka. But unlike her and her pupil the other members aren't completely thrilled about dealing with pupils. And one more little secret. Sophie is the princess of Quartet Night. The four males all love her. Literally. Come with me on an adventure and see what awaits the groups.