Yu, a female teacher and wife, is set to go on a preview trip for a school excursion. She was strongly opposed to staying overnight with colleagues, knowing how "insidious" the teaching profession can be, but since it's work, she has no choice. She tells herself that even between a man and a woman, nothing could possibly happen in just two days and one night, so worrying is pointless. Surely... there's no way they'd be having sex... right?
