The protagonist recently transferred into his/her current school.

College transfer is the movement of students from one higher education institution to another and the process by which academic credits are accepted or not accepted by a receiving institution.

However, transferring can be done by students at schools of any level of education, high schools being the most commonly in visual novels. Younger students may transfer because of a parent's job changing to a new area, but in visual novels it's often the result of the student's personal, and often secret or mysterious, circumstances.