My name is Kunisaki Juuichi. I attend Yamagata Academy. Because I'm serious and a top student, everyone calls me ‘Sensei’. My motto is to get along with everyone and enjoy school life to the fullest, but actually, I have a secret...! There's a girl I'm interested in. She's Sumine Masuzu from my class, known to everyone as ‘Suu-chan’. She's a gal, but quiet and a bit down. Apparently, she doesn't study much and is in danger of failing a year. Her house happens to be in the same direction as mine. Today, she invited me to walk home together, but... “Congratulations! You won the hot spring trip lottery!” What?! Suu-chan hit the grand prize in the lottery we drew on the way home!? To my astonished look, she said. “Sensei, wanna come with me?” My heart's racing nonstop from this invitation from the girl I'm interested in! When I hesitated, saying it's impossible, Suu-chan pressed on. “If it's with you, Sensei... maybe I could study?” “And if you come... I'll take your virginity♪” That line was too tempting—I nodded in agreement... No prep possible, certain to go off the rails. And... kinda moved. A four-night, five-day hot spring trip filled with shock and healing begins...!