Soon to be Four

The Marauders are back in their third year at Hogwarts, when they meet Lukari Lakasse. She's a strange girl with a strange past,and they can't help but be interested. James, Sirius and Remus might have found another addition to their group, and another interesting feature in the group of Hogwarts students. Will they soon be the four Marauders? (Peter doesn't count, duh.)