O Maidens in Your Savage Season Vol. 4 (manga)

THE NEXT STEP

Kazusa's crush and childhood friend, Izumi, suddenly seems awfully close with Nina--who's pretty, cool, and much more mature than Kazusa... Crushed by a ballooning feeling of suspicion and inferiority, Kazusa starts to lose sight of her relationship with the both of them. And when the Literature Club sets out on an overnight trip, each girl brings with them a whole lot of baggage!